Table of contents
It's been a while, TASVideos.
Game objectives
- Emulator used: Bizhawk 2.9.1
- Aims for fastest time
- Uses 2 players
- Plays at Hardest difficulty
- Does not abuse death or use continues
- Manipulates Luck
About this run
I didn't plan on making this run, having somewhat retired after my Metal Slug 3 run. At the time, I didn't think there were too much improvements that could be made for X2poet's run and the nature of FBA-rr (the only TAS emulator available for Arcade games at the time) killed any motivation. That began to change when I saw a 2 player speed run done by Topeng and Sukimos showing off some new potential strats. More new strats were developed by Metal Swag, who managed to push the 1 player level 4 time down to sub 15 mins (previous runs in this category were typically around 16 mins). These new developments and the release of Bizhawk inspired me try to adapt the new ideas for a 2 player level 8 TAS.
This run manages to beat X2poet's by 10299 frames or 02:54.01. While some of it comes from opting to end input early, the majority of the improvements come from the main gameplay from using new strategies and optimizing everything better.
Weapon Damage
- Pistol: 10 per shot
- Melee attack (knife, kick): 30
- Grenade: 100 (after the initial 100, the smoke can do 1 damage per 2 frames twice to certain enemies)
- H: 10 per bullet (pressing fire once shoots 4 bullets)
- 2H: 20 per bullet (pressing fire once shoots 4 bullets). There is a 2 frame delay that occurs in between rounds when you try to fire while standing (regarding of which direction you’re firing). This delay does not occur when you fire while crouched. Firing the first round while standing and the second round while crouching also eliminates the delay. Unfortunately, there are no workarounds if you need to shoot upwards.
- L: 8 per 2 frames (1 bullet consumed every 4 frames)
- R: 30 (against certain enemies, after the initial 30, the smoke can do an extra 30 damage 6 frames later, followed by two additional instances of 10 damage per 4 frames, resulting in a potential total damage of 80)
- D: 30 (the smoke can do an extra 1 damage to certain enemies)
- I: 30 (the smoke can do an extra 10 damage to certain enemies)
- C: 30 (the smoke can do an extra 10 damage to certain enemies)
- G: 100 (the smoke can do an extra 50 damage to certain enemies)
- F: There are two parts: the "main" flame and the "side" flame. The "main" flame does 20 damage per 2 frames while the "side" flame does anywhere from 0-5 damage per 2 frames. The "side" flame damage depends on how much it covers the enemy. The "main" flame can hit an enemy a maximum of 13 times for a damage of 260. The total max damage you can do with F is 314.
- S: 200
- Firebomb: 80 (The smoke of the firebomb can do 15 damage to other enemies that are close to the intended target)
- Slug Vulcan: 10
- Slug Cannon/Missile: 200
- Slug Attack: 400
Note: Interestingly, big weapons cannot be obtained normally in this game.
Tricks/Glitches
- Turnaround Cancel
When you attack while crouching, you can immediately turn around and do something else. For certain weapons, you can immediately turn back around and attack again. This cancels the delay between time you fire a weapon once and the time you can fire again, allowing you to fire once every 4 frames. This can also be used to save bullets with some weapons like H, 2H, and L. This can also be done with grenades and melee attacks. However, when doing this with melee attacks, you must wait 2 frames before turning around to cancel the attack animation, but it is still faster than just crouching and attacking.
- Faster H
Pressing fire once with H shoots 4 bullets, each doing 10 damage every 4 frames. It is possible to fire H such that the 2nd and 3rd bullets are bunched together, doing 10 damage every 2 frames. This is done by pressing fire -> waiting 4 frames -> pressing fire and down. This cycle can be repeated by using turnaround cancel and pressing fire again. You must shoot at least one bullet normally before you can fire two bunched bullets.
- Faster Vulcan
Pressing fire once with slug vulcan will initially shoot 5 bullets, each doing 10 damage every 4 frames. Depending on when you press fire again, the slug vulcan will shoot different amounts of additional bullets (ranging from 1 to 5) 4 frames after the 5th bullet. When you press fire on the earliest frame where the slug shoots 5 additional bullets, they will be shot 2 frames after instead, making it slightly faster. I’m not sure if this works with all slugs, but it worked with the two slugs that were used in this run.
- Damaging enemy vehicles with Nadia’s taser
Nadia is unique in that she will use a taser as her melee attack instead of knife. Like other melee attacks, it’s only usable against bio enemies (soldiers, zombies, mummies). However, you can damage armored vehicles if there is a soldier near it by intentionally missing the soldier with the taser, but having the hitbox overlap with the enemy vehicle. This makes Nadia a must in this run as you will see that I get a lot of use out of this trick.
- Speed boosting off slopes
When jumping off slopes, you can a speed boost for a few frames. The amount of boost depends on which part of the slope you jump off of. In general, it’s not worth walking for a few frames just to try to get a bigger boost. Ideally, you should time/position your jumps such that you jump off the slope at the position that gives you the largest boost.
- Moonwalking
The most important trick in the entire series. Can be initiated by pressing up and then holding the key opposite of the direction you’re facing. The moonwalk can be extended by pressing up before the character turns back around.
Boss Notes
Metal Slug 4 is unique in that some of the bosses have interesting properties which are listed below. Two of these properties are disadvantages, requiring some workarounds.
- Full damage from weapon smoke
For some reason, the mission 1 and 5 bosses take full damage from weapon smoke. This means the R is able to deal up to 80 damage, making it one of the best weapons to bring against them.
- 100 Hp blocks
The mission 1, 4, and 5 bosses have their total health divided into blocks of 100 Hp. These bosses have separate ram addresses that show the total Hp and the current block Hp. Dealing 100 damage will clear the block and take you to next block. The caveat is that excess damage does not carry over to the next block. For example, if there is only 20 Hp left in a block, throwing a grenade will only do 20 damage. This means we have to be careful about when we use certain weapons (like R and grenades).
- Taking damage from only one weapon
A few bosses have an interesting restriction where they can only take damage from one weapon at a given time. This is the case for the final phase of mission 4’s boss and mission 6 bosses (excluding Allen).
Other Things to Note
- Jumping has a higher max speed than walking, making it faster most of the time. Depending on the distance that needs to be covered, walking may sometimes be better than jumping.
- There are two types of jumps: standing (jumping without holding left/right) and moving (jumping while holding left/right). Standing jumps gain height faster, linger at the peak longer, and descend faster. Moving jumps gain horizontal speed faster. Both types of jumps still spend the same amount of time in the air (you will land on the same frame).
- Holding left/right for at least 2 frames before jumping will gain more distance than pressing left/right and jump at the same time. This means that whenever you enter a new area (whether you descend from a parachute at the beginning of a mission or walk in from the left), it’s better to hold right/left for 2 frames before jumping.
- When you’re exiting out of an area, it’s faster to jump out of the area rather than walking out of the area, it can save 4 frames.
- While firing pistol, H, or 2H upwards, jumping will cause the bullets to deal damage 2 frames earlier than if you had stayed on the ground since you’re closer to the enemy. However, as you land, there will be a 2 frame delay, reverting you back to the same rate if you had stayed on the ground. In short, when fighting enemies above you, jumping while firing the last round of bullets needed will allow you to destroy them 2 frames earlier.
- The rng in this game is determined by your inputs. Any input you make (even simple actions like holding right for 2 frames) can change the rng.
- There seems to be an rng element that determines when the screen will scroll after fighting certain enemies (mainly helicopters). It seems to be determined by how/when you destroy the enemy and the actions you do in between the time the enemy is destroyed and when the screen scrolls.
Stage by stage comments
(Will be updated within the next few days)
I opt to a few extra frames to turn on the setting that displays the level at the bottom of the screen. It’s not necessary, but I thought it left no doubt to have “Level 8” displayed throughout the run (interestingly, Metal Slug 1 is the only one that has this on by default).
Like X2poet, I decide to use Nadia and Trevor as they are exclusive to this game (Nadia is the only character that’s necessary). However, I spend 2 extra frames to select Nadia as player 1 and Trevor as player 2 (X2poet had them the other way in his run). This is because I found that having Nadia as player 1 puts her in a better position when entering areas (allows her to reach enemies quicker to use her taser).
- Part 1
- I opt to use turnaround canceled pistol shots to destroy the first truck asap before moving to the right (the explosion also kills the remaining soldiers fast enough that the screen scrolls without another extra one walking in). While fighting the first tank (melty-honey), I kill the shield soldier on the left by timing a pistol shot such that it will hit the soldier directly when he spawns. I tried to manipulate the screen to scroll asap after destroying the helicopter.
- Part 2
- The plan for this mission was to take at least 100 bullets of 2H and all 30 bullets of R to the boss battle so I used a lot more grenades in this section, saving a lot of time. After fighting the first tank (melty-honey), I was able to get the screen to scroll faster by killing the two soldiers on the left simultaneously (killing the first one will cause two extra ones to spawn, which is what happened in X2poet’s run). After destroying the last tank (di-cokka), I found that you don’t need to ascend the stairs asap. The screen will transition at the same time as long as you get there fast enough. So I tried to minmize the lag so that the screen
- Boss - Brave Guerrier
- Part 1
- Part 2
- Boss - Toschka Dalanue
- Part 2
- Part 1
- Part 2
- Part 3
- Boss - The Iron
- Part 2
- Part 1
- Part 2
- Part 3
- Boss - Big John
- Part 2
- Part 1
- Part 2
- Part 3
- Boss - Sea Satan
- Part 2
- Boss - Allen O’neill
- Final Boss - Amadeus Mother Computer
End
I opted to end input early. The only difference in the two endings is the cutscene that plays after the final tally up. Ending it early like this also allows the run time to be more comparable to the timing used by RTA (which ends the moment Amadeus is destroyed).
Thanks
- X2poet, for his TAS. No matter how improvable his runs end up being, he deserves a lot of credit for setting the bar. It's amazing that he managed to TAS the entire arcade entries in a year with FBA-rr.
- Topeng and Sukimos, for their 2 player run.
- Metal Swag, for his work in pushing the 1 player category to its limits.
- mtvf1, for the lua scripts.