Submission #4864: dunnius's MSX Metal Gear in 26:28.04

The TAS is complete after a very long time and a number of test TASes. This beats my test TAS by 70.6 seconds due to better routing and lag reduction. This game is very laggy, so lag reduction ended up playing an important role in route planning, although I only realized that when I was working on the final version. This caused me to redo small parts of the TAS as I found ways to reduce lag, although the silencer was the one time where I had to stop TASing to test way ahead to see if it reduced enough lag. The hardest part was the desert, where I had to reduce lag without excess movement while dodging scorpions.

Luck can be manipulated by input at any time, which makes it easy to manipulate enemies and cameras. However, it would seem that the choices for manipulation are somewhat limited, but it is hard to tell without a bot. It could be that a decision is made at certain frames based on the enemy's internal timer, and is a coin flip. For example, the decision in alerts could be change direction or shoot. It is somewhat difficult to tell how scorpions can be manipulated, though.

This game is very laggy. Random lag will start occurring when there are only three enemies or objects on the screen, not counting Solid Snake. With four objects lag will be more frequent, and more than that will generally have consistent lag frames. The easiest way for the number of objects to increase is bullets from anyone. This is something that is likely to happen in alerts, so if bullets can not be prevented with manipulation, or if spawns will cause too much lag, then an alert may not be worth it. Sometimes shooting an enemy will cause some lag, so that should only be done if it ends up removing more lag. The best time to shoot is when there will be lag frames from lots of objects because it will not cause more lag. Areas like land mine fields or bridges are super laggy, so they should be minimized when possible. Laser cameras will cause some lag frames when they shoot, and the flying guards tend to be a bit more laggy. It is possible that taking damage may cause a lag frame, but it is hard to tell. Sometimes there will be an extra lag frame during a screen transition if buttons are held down, so input can cause lag.

Solid Snake moves two positions at a time in either the x or y direction, which I call a position group. Normally it takes two frames for a position group, but it can be one or three. Obviously if there is a lag frame, then it will be three. There are some screens where a position group will take one frame, but it is paired with a three frame that occurs either before or after, but not necessarily on consecutive position groups. I suspect this has to do with the timing of the MSX because a screen transition will also balance this out, so these screens can be considered as if it was every two frames. Also, lag frames will not happen on those screens because having enemies on the screen forces the position groups to occur every two frames.

Solid Snake can clip into a wall by a position group when entering from a corner, which can save four frames. It is also used to shoot a flying guard that keeps its hitbox in the wall.

Choosing when to go into menus was an important part of route planning. Some screens take longer to reload after the menu or have lag frames during the menus if that screen is being laggy, which includes alerts. So when needing to switch items, I had to test all of the screens up to where the item is needed to find the fastest. As more items are obtained, it takes longer for the menu to load, but it was only two extra frames at the end of the game. Sometimes going through blank areas in the menu is faster if they do not have a lag frame. They are less likely to lag because they do not need to draw anything in the current equipment box. This means that taking a longer path on the blank areas can be faster if it lags less.

Guards can be punched out for items, although it would seem that enemy #4 (identified in the HUD script) is the only one that drops items. The two possible drops are rations and ammo, and of course there is a chance of no drop. This is easy to luck manipulate by random input. It costs 56 frames to punch out a guard, which requires 3 punches. Punching can be done 20 frames after the previous punch, but Solid Snake can move 1 position group to do the second and third punch, which saves 2 frames each. So it costs 20*3 - 2*2 frames to punch.

It is faster to skip the gas mask because that avoids a major detour to get it. Skipping it also reduces the number of equipment switches for each gas area to one instead of the normal two, saving at least 40 frames. There are three gas areas in the game, and each one requires a ration to replace the gas mask, so that makes that one equipment switch necessary, plus a small cost to menu to the ration. It costs a second to get a ration from a guard drop, so using the ration ends up slightly slower for each gas area, but not anywhere near the time for the detour.

Solid Snake becomes invincible for a short time (30 position groups) when taking damage, which is useful to avoid more damage from something else, or instant death. One use is taking 2 HP of collision damage to avoid the 8 HP bullet damage, another is using the 2 HP gas room damage to avoid the 16 HP damage from land mines (although gas damage occurs every 32 position groups, so there is a 2 position group window to take land mine damage.) A big use is using bullet damage from the tank to avoid the instant death from the tank collision to skip fighting the tank. Dying does not save time because it rolls everything back to the last checkpoint.

Every five prisoners rescued increases Solid Snake's rank. The starting rank is 1 and the max rank is 4, so a maximum of 15 prisoners need to be rescued. There are more than 15 prisoners available, so part of the route planning was to figure out which ones are the fastest. Fortunately this ended up being rather easy.

Ranking up restores the HP to the next rank's max HP value; 24 HP for rank 1, 32 for 2, 40 for 3, and 48 for 4. This allows for plenty of damage boosting, and also helps reduces the number of rations needed for the gas areas.

I am not completely sure how it works, but alerts can be ended by shooting enough guards (especially spawns) and/or changing screens, though I do not see anything consistent. I used trial and error, but I am going to investigate this further. Also, ending an alert disables cameras and infrared beams for that room, which was useful in the TAS.

If two enemies are close together, then they will both take damage from the same ammo. This is used a few times in the TAS.

Getting the hand gun is faster because it is used to end alerts, which would take too long with punching. It is faster to get alerts and end them. The silencer is obtained for a couple reasons. The first is that the boss in that room causes lots of lag frames from the four enemies that shoot, so it is faster to kill some of them anyways. However, all four can be killed very quickly, and with a small time loss, using good luck manipulation, which the TAS does awesomely using overlapping hitboxes. Also if the silencer is not obtained, then all four enemies of the boss will return when coming back from the grenade launcher room. The second reason is that the silencer saves time because of being able to shoot enemies to reduce lag or prevent raising laggy alerts. This is mostly useful in Building 2 Floor 2 where spawns require 2 bullets to be killed. Getting the silencer loses around 100 frames, but around 60 frames are saved in the same room after getting the grenade launcher. I calculated the net savings to be around 3.5 seconds. The silencer room was where I had to suspend working on the TAS to see if getting the silencer saved frames later on.

In some cases, collision damage will only cause a single exclamation point alert which can be ended quickly by shooting the guard(s) (there will not be spawns, and ending the alert will also disable cameras), or by changing screens. This is only useful before getting the silencer because shooting without it before the collision alert will cause a double exclamation point alert. Another way to get a single exclamation point alert is being seen by a guard (though again it depends on the guard) which is useful in the center room of Building 2 Floor 1 where I use a weapon that would have caused a double exclamation point alert. Once there is an alert, the type of alert cannot be changed.

The direction that Solid Snake faces (up/down vs. left/right) when placing an explosive is important. Each placement has one direction that is faster than the other by a couple frames. It depends on the room shape and the direction Solid Snake is coming from.

When getting items from tables, the table can be clipped into from underneath five x position groups earlier than using the usual wall clipped position in the center of the table. Solid Snake can move left or right when clipped, but moving up is disabled with any x position other than the initial clip position, or leaving the clipped boundaries of the table. The item can be obtained early by going toward the item by one x position group, although large items like the grenade launcher and rocket launcher do not require that. This saves 16 frames per item, and 20 for each large item. There are two places where the room's door is at the top which saves an additional 12 frames because going down and around desk is not necessary when clipped.

There is a glitch involving the Save Menu that causes the screen to get redrawn, causing three beneficial effects. The input sequence is F1 (pause), F5 (bring up Save Menu), escape (leave Save Menu), and F1 (unpause). One benefit is item duplication, which is straightforward. Another is disabling electric floors, which avoids a detour to get remote control missiles or more rations, and using the menu glitch is faster than using a remote control missile and equally as fast as using a ration. The third benefit is resetting the flag that an item was dropped for the screen. Normally only one drop can happen per screen, but this makes the limit be the number of guards that can drop. When doing multiple Save Menu in a row for item duplication, for some reason the Save Menu after the first will go away much quicker than the first one. This is why item duplicating is faster for dropping for two or more duplications.

In the small rooms that have one door that needs to be opened, a few of them are set up in a way where it is faster by a few frames to open the door immediately. There are a couple factors for this. One is that the hitbox for an opened door is bigger than a closed door which means that it takes less time when coming back to the door. Going into a menu after opening the door might shrink the hitbox back to the closed state, but this affects when menus should be done. The other factor is the initial placement of Solid Snake in relation to the door since it costs frames to walk back to the door.

When there is an explosion from grenades or rocket launchers, the next shot is prevented from happening until the explosion animation is done. There is a counter for the animation that runs while a menu screen is loading, which means that frames can be saved by going into a menu, but only if a weapon or equipment switch is needed. This creates an optimal time for a switch. The best frame to go into the menu is the first frame after the hit is counted, or in the case of grenade pairs, the first frame after the second grenade hit is counted.

An interesting quirk not shown in the TAS is that destroying the Bulldozer Tank will also destroy the Tank if it was skipped. It appears they share a common memory address.

When receiving a message on the transceiver, the text can be skipped and still count. The earliest frame to hit F4 is when the signal bars are full.

The scorpions cause lots of lag when there are more than four of them on the screen. So a main goal of each screen is to shoot two of the six scorpions as quick as possible without causing lots of lag when shooting them. So most of the time they are shot at or near point blank to minimize the time that the bullet is on the screen. RNG manipulation in the desert is a pain because the scorpions love getting in the way (slightly more difficult to manipulate), and the hitboxes are not centered on the sprites, which makes it more difficult to plan a route to avoid getting poisoned. Also adding to the difficulty is that only the two primary directions can be traveled (Going from building 2 to building 3 is up and left, coming back is down and right) because non-primary directions costs four frames. This is done once because it ended up reducing lag.

The entire sequence of rescuing Dr. Pettrovich and his daughter can be skipped because that only reveals the pattern for the explosives on Metal Gear rather than setting a flag to enable the explosives, which is what NES Metal Gear does. So by knowing the pattern, which is always the same, Dr. Pettrovich is unnecessary.

In the escape ladders, there is a glitched x position which is the leftmost position that the ladder that can be climbed. Solid Snake will climb the ladder off center and will ignore the top of the ladder by continuing to climb up the wall. This means that the rightmost ladder can be used saving some time.

In the card 1 truck, it is faster to manipulate the guard to run to the right (no shooting) and take two damage from collision. This is because going up to dodge a bullet requires going up past the bottom of the card's hitbox, wasting frames.
The guard that gets punched out drops a ration.

The intentional alert from the camera is done because because avoiding it wastes too much time. The next screen has collision damage to avoid bullet damage, and also because collision is unavoidable.
After getting the ammo in the following screen, there is a specific number of guards that are shot to end the alert in the room after the gas room. The guards that are in the way are shot, and four frames are lost to turn around to shoot the third guard. This also has the added benefit of removing 19 lag frames because the number of guards is kept down. It also cuts out 72 lag by ending the alert immediately after entering the room after the gas room.
The roller room is the best place to get plastic explosives before they are needed.
The guard in the next room will "!!" with a collision, so the options are take the longer lower path, go up and around the guard, shoot, or punch. Because the alert can be ended at the end of the following screen with only several lag frames, it is faster to shoot the guard.
Outside the card 2 room, the guard will only "!" from both collision and being seen, which are used in that order.
In the room after the electric floor, the guard gets punched to avoid a "!!" from being seen. The guard could have been shot, but there was not enough ammo to end another alert.
The northwest prisoner is done after the silencer and grenade launcher because exiting the room puts Solid Snake at a lower y position, so that saves 8 frames.
The silencer boss is taken down with 6 bullets because of hitbox overlap.
In the room outside the silencer and grenade launcher after coming back from the prisoner, there is a forced "!" that I was unable to luck manipulate away. Fortunately, it does not cause any lag frames.
In the room outside the east elevator, there is a forced alert because of Solid Snake's position. It is possible to enter from a lower y position to avoid alerting, but the best case loses 20 frames. Because there are less lag frames alerting, that is chosen.

The guard is punched out to get an ammo drop, which is needed since there is only 1 bullet left, but the real reason is to get ammo for the grenade launcher. This is 1 of 5 ammo that is needed.
When getting captured, it is faster by 5 frames to make the second guard appear at the top of the area. That is done by putting Solid Snake at y position 152. The x position where Solid Snake moves down in that screen is at the right edge of where the capture happens.

Shoot Gunner causes some lag frames, so the first pass is done to get out of that area as quickly as possible.
In the card 3 room, the order of getting the card and the ammo does not matter because both paths take the same number of frames.
Four ammo boxes are obtained using three Save Menu Glitches to get the remainder of the needed five ammo boxes for the grenade launcher. I would have got all five ammo here, but I needed ammo for floor 1. Also, there were two other guards that could have been punched for ammo, but they were slower.
Shoot Gunner is skipped because even though he causes lag, 12 lag frames, it would have cost more to switch weapons an extra time, plus some lag caused by shooting him.
In the main part of the basement, I tested getting the uniform before the bomb blast suit, but that was 196 frames slower.

In the room outside the elevator, it is faster to go to the right side of the boxes by 12 frames. It is possible to avoid the camera alert, but it costs 45 frames, plus multiple seconds in the next room because of the sleeping guard's message, plus an alert would happen anyways from taking the short path through the infrared beams.
The prisoner in the southeast room is rescued after Machine Gun Kid because it saves an equipment switch.
Going up the right side after that prisoner saves 20 frames over the left.
The alert from the infrared beams is not ended in the room outside the elevator because it is faster in the room before, also the alert that happens in the room outside the elevator does not cause lag.

The room to the left of the elevator has random lag from the guards, so the time in that screen is minimized. There was one lag frame.
The suspension bridges are super laggy, so that is also minimized by entering and exiting the bridges on the left side.
One of the flying guards tries to keep its hitbox inside the wall, but by wall clipping and then shooting down, the guard gets shot.
I tried to be as entertaining as possible while waiting for the twenty grenades to explode on the Hind-D, but it ended up not working the way I wanted because of the small size of the cock- pit's hitbox that prevents lots of movement. It was impossible to hit it from below without losing time, unfortunately. An explosion cancel is used to switch equipment.

The minefield outside the card 4 truck is also very laggy, so the paths minimize the time in the screen both going into and out of the truck.

The first two screens are laggy minefields, so again the minimum time is spent in there.
The sound cancel of the tank shell being shot caused by switching to the uniform when the sound starts does not save or lose any frames; it was done for entertainment.
The guards outside of building 2 have two messages. The second one can be delayed without losing frames because even though it has a huge hitbox, it is inset from the boxes in the x direction so it can be triggered from any y position. I picked one where Solid Snake is standing in the text.

In the central room, the only way to kill the guards from the upper left area is by shooting grenades. This is done to reduce lag from from the forced "!" alert from being seen because of not waiting. But that alert has a great benefit. The grenades will cause a "!!" when they explode, but only if there was not already an alert. The second grenade had to be thrown from a lower y position otherwise it will go off the screen and despawn. This makes taking the 4 HP deep water damage save more frames because it makes the path to go around longer.
In the antenna room, the guard was manipulated to keep moving to avoid an alert before being punched for a ration drop.
Back in the central room, the guard is punched to get another ration drop, which costs an additional 8 frames to get because it drops in a lower position. But this extra ration pushes card 5,6,7 down 1 slot to make it more aligned with cards 1,2,3 saving 2 frames each switch between columns, except the very last one that loses 2 frames because the ration is in a slightly worse position. This saves at least 8 frames (possible lag frames can happen) in total for menus compared with getting the last ration drop later, so it is probably only slightly faster to get this ration, at least equal.
Deep water damage of 4 HP is done to save 8 frames because there was enough health left to fit that in.
The "!" alert is forced again from being seen, but it does not lose any frames. The same is true for the infrared beam outside the elevator room.

The alert for the entire roof is forced, which means there are lots of potential for lag frames. So the entire roof has massive luck manipulation to make the guards shoot as little as possible, and/or be in a position to get shot. It appears that around 4.5 to 5 seconds of lag was removed on the roof compared to my WIP, which is an amazing amount.
In the second screen (to the right of the elevator screen), there is an unwanted spawn and collision damage that I could not manipulate away, but luckily there was enough HP to take that.
In the fourth room (the one outside the card 5 room), there is again a flying guard that tries to keep its hitbox in the wall. This time the position is 1 movement group further into the wall than the wall clip, and the bullet grazes the wall. This costs four frames because moving back into the position for the wall clip had to be done.

I tried shooting fire trooper because the fireballs lag really bad, but the fireballs block some of the shots, so I could not land the necessary 15 shots, and it would seem that shooting caused even more lag because of the number of fireballs. So the planned collision damage ended up being used.

In the room outside the elevator, the "!" alert is forced, but I manipulate the guards so that only the bottom 2 shoot since their bullets hit the wall quickly, reducing lag frames.
To get past the lower Arnold without getting hit or losing frames, a rather specific path must be taken in the lower area. Go to x position 22, then y position 168 or 170. 170 is the lowest y where Solid Snake does not take damage from Arnold. This makes Arnold turn around early so he stays away from the southeast door.
The southern rooms have 4 guards, so one gets shot quickly to avoid random lag, which is done again after the prisoner room.
After getting the rocket launcher, the best place to get ammo for it is the eastern room punching guards for ammo. The upper right guard does not drop anything, but the other two do. The Save Menu Glitch is used, and exiting and entering reloads the guards so the process can be repeated. Only four ammo boxes are needed (8 rockets) to defeat Arnold, and more ammo will be obtained later.
Arnold gets knocked back when hit with the rocket launcher, so that makes it a bit easier to make the rockets hit Arnold the frame after they are shot. On the lower Arnold, the last rocket was shot facing down from a position as high as possible to save frames going to the top Arnold. The top Arnold was shot while Solid Snake walked to the left to where the card will appear, the upper left. The explosion cancel was used to avoid shooting backwards a third time saving a couple of frames.
In the south east room (the one outside the room outside the elevator) the guard is punched for an rocket ammo drop for the Big Boss fight. This is one of two drops needed. The drop costs 8 frames to get, but this prevents the guard from falling asleep and wasting time with the sleep message. In the roller room, triggering the pitfall costs a frame so the perimeter of the trigger point is walked. I suspect the roller is actually multiple objects.

In the deep water, trying to avoid damage by switching screens in the deep water like the NES version does causes an extra damage. This is because the terrain counter stops during screen transitions, and the transition causes another step which increases the terrain counter just enough for an extra damage.
20 Explosives are obtained using the Save Menu glitch three times. It is done at this time so that explosives are only collected twice in the game.

Although left is a primary direction, moving too far loses frames. So there is a limit on moving left to be in a good position for the Building 3 Gauntlet. Fortunately, the scorpions were not that bad to manipulate, and did not cause too much lag.
In the gauntlet outside building 3, shooting guards to reduce lag is a priority. These guards love to shoot because they always shoot initially. The starting x position is the leftmost to shoot the guard on the right side of the door, which minimizes the time in that area. Both that guard and the one to the left are manipulated to come out and walk forward so they can be shot as soon as possible. Because only three of them will shoot initially, the one to the right of the door is manipulated to be the one that does not shoot.

In the building 3 entrance room, the initial set of guards plus one spawn are shot to keep the number of guards to a minimum while placing the explosive and afterwards since the explosives have to stay equipped.
In the pitfall room, triggering the pitfalls do not cause lag, so all of them get triggered. The first one was triggered at the leftmost position possible, which also reduces lag by minimizing the time in the previous room. Unfortunately there is no glitch to stop the pitfall from growing.

Going down the left side of the center wall saves two frames. The same is true coming back.

In the building 3 entrance room again, I managed to make two of the spawns despawn (this can only be seen with the HUD) which seems to happen only on a particular y positions. It made it easier to luck manipulate, and reduced lag. This sort of thing could be useful elsewhere if I knew how it works.

In the gauntlet again, the guards are manipulated to get shot quickly to reduce lag. Shooting a third guard is faster because having a bullet on the screen does not cause any more lag while the other guards' bullets are on the screen.
The compass is not needed to be equipped coming back from building 3, which is different than NES Metal Gear, so I did not think about that until after I completed the desert, which took a while. So I had to redo the entire desert which again took a while. This part of the TAS took the longest (a couple months) because of the luck manipulation.
In the second desert screen that has scorpions, I make use of the overlapping hitboxes to kill two scorpions with one bullet. I also demonstrate the off center scorpion hitbox by having a scorpion be on top of Solid Snake without causing poison status.
In the third desert screen, I was forced to shoot to the left to avoid getting poisoned, but this also reduces lag. The first pair of scorpions that die on the same frame were shot with 2 separate bullets, but the second pair were done with one because of the overlapping hitboxes.

The room at the end of the trench with four guards has random lag, so the time in that room is minimized by entering at the left side. Going left is done a little at a time during the deep water. A guard gets shot to reduce lag, and another guard is punched for the other ammo drop for rockets, the second of two for the Big Boss fight.
It is faster by around 2 seconds to kill Coward Duck with the handgun rather than with the rocket launcher. The fight itself is a little bit slower because of lag, but the setup is much faster because it skips 2 weapon switches and it skips punching a guard for an ammo drop for rockets. There is a maximum of 6 bullets on the screen at a time, so there is a small wait before shooting again. But because Coward Duck is moving the right at that point, only 2 shots can hit him before he hides behind the prisoner. The last 2 shots are delayed until he starts to come back out. These delays are okay because the time is spent avoiding the pitfall, or walking to the left to where the card will appear.
Back in the room with the guards at the end of the deep water, the time in that room is again minimized. The one guard gets shot to avoid a collision alert and reduce lag.

The compass is always required when going from building 2 to 3, so it is equipped.
In the desert, I followed the same general path as the first time through the desert. The RNG was slightly different which caused more lag than before.
In the gauntlet outside building 3, the same general path from the first time was used again. There was much more lag than before because of different RNG despite the similar guard pattern.

In the building 3 entrance room, the initial guards are shot like before, but the spawn is not shot because that would be 3 frames slower due to 8 frames of extra movement for shooting twice. It turns out that switching to the explosives is 1 frame faster in this room, but doing so caused a couple more lag frames from different RNG, so it was done later.

In the room outside the elevator, the path chosen was one frame away from getting hit by the laser.
In the next room, taking damage from the two laser cameras is done because it is faster than waiting 46 frames each time. A ration is required later no matter what, so this makes use of the extra HP.
In the first gas room, when switching equipment and using the ration, it is faster to go up the list instead of going to the right of the items and up where there are blank spaces because both ways have the same amount of lag. This is likely due to the number of objects in the room.
In the second gas room (the one with land mines), the I-frames from the gas damage are used to avoid the damage from setting off the land mines. I found this by accident when I was at this point in the TAS. Then I realized that I could use this to clear the land mines because that reduces lag. I looked at a number of paths to find the best one that saved 42 frames.

The laser cameras in Metal Gear's room cause about six lag frames each time they fire, so the path to place the explosives has to reduce the number of lasers. One laser at the beginning is forced because both cameras go the center at the same time making it unavoidable. One laser at the end (left side) is unavoidable because of walking to the door on the left after placing the last explosive. I barely managed to find a way to get no other lasers during the explosive placement, although the laser that does fire at the end is from the right side camera, but that was after the final explosive. Because only one laser can fire at a time, the left camera does not fire, so it works out in the end.
The equipment switch can be done while the explosion is in progress, which saves 7 frames and looks cool.
In the Big Boss fight, all rockets after the first one were shot at the first available frame, so there was no waiting around.

They can be found here: [dead link removed]

This run is dedicated to my friend George McIntire, who died a few weeks ago at age 74.

Samsara: Giving myself an excuse to learn openMSX Judging!

Samsara: This was phenomenally planned out and executed! Both reading the submission text and watching the movie, it was clear that every little detail was optimized to its fullest extent, which is very impressive over the course of such a long-term project. Well done!

Viewer feedback is unanimously positive, and the run shows amazing technical prowess. Accepting to Moons!

fsvgm777: Processing.