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Submission #4326: Auxeras & VicoV's Saturn Bomberman "Master Game" in 10:12.86

Console: Sega Saturn
Game name: Bomberman
Game version: unknown
ROM filename: 304 Saturn Bomberman (U).iso
Branch: Master Game
Emulator: BizHawk 1.6.1
Movie length: 10:12.86
FrameCount: 36832
Re-record count: 3770
Author's real name: Lina D. & Vincent D.
Author's nickname: Auxeras & VicoV
Submitter: th2o
Submitted at: 2014-06-05 13:26:49
Text last edited at: 2017-05-28 15:28:39
Text last edited by: th2o
Download: Download (7829 bytes)
Status: published
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Author's comments and explanations:

(Link to video)

This TAS runs the Master Game mode of Saturn Bomberman in fastest time with no damage takes. In this mode a lone bomberman enters a temple and climbs through its 20 floors (including 5 bosses). The choice of going no damage was made since no way was found to speed up the run significantly by taking damage: unlike in SNES Super Bomberman, the invulnerability frames gained by getting hit are very short. So instead of looking sloppy just staying still in front of bombs to save a couple frames the choice was made to go for constant grazing of explosions and enemies.

Game objectives

  • Authors: Auxeras & VicoV
  • Emulator used: BizHawk 1.6.1
  • BIOS used: Sega Saturn BIOS (J) (1.00)
  • Intended Tier : Moons
  • Fastest completion time
  • no damage

Comments

Explaining the basics of a Bomberman game is probably unnecessary here, so let's talk specifics right away. This game has two modes apart from Versus, one called Master and the Normal mode. This run is about Master. The conditions to clear a level in this game mode are to kill all enemies and reach a ladder which only descends once you're the done exterminating. While this sounds straightforward enough, the tactics used will vary thanks to the use of power-ups distributed along the way. About the power-ups, contrary to the Normal Game mode, not all of them are kept permanently: the power glove (allowing you to throw bombs), kick (letting you shoot bombs away) and remote bomb (ability to detonate bombs at will) are floor-local, which isn't too bad in a sense since it keeps things varied and hopefully entertaining.

The exact workings of the RNG remain unknown for now, but it seems to cycle only on enemy action, and enemy actions definitely depend on your current position (down to the subpixel), meaning simply trying to optimize your route by the smallest amount can result in disaster two levels later. So the process applied to route planning was:

  1. complete multiple test TASes while changing boss fights (easy way to change the number of enemy action cycles without losing time) to determine what good enemy movement patterns could be hoped for, and 
  2. try to complete a run including all the best patterns.

Since this amounts to brute-forcing it could definitely be improved just by iterating more. The run submitted has roughly the fastest completion time observed for every single level (and of course the best overall time).

Stage by stage comments

Floor 1

At the very start bombs are few and explosions are small. Since the concepts applied remain the same for all floors without power-ups it serves as a nice introduction though. The basic principles are:
  • Explosions are thinner than they look. You can always enter a tile on which an explosion is occurring before it visually disappears, though how early you can do so varies (according to your speed modifier mostly).
  • Your character's hitbox is small. It's a single pixel actually. As a result you can be visually standing on a burning tile and not get roasted, since your character's 'center' is actually one tile to the side.
  • Bomb timers are long, and can be shortened by creating chain reactions. Thus every time it is possible you should try to create one, placing a first bomb as soon as possible to let its timer run while walking to set the actual bomb whose explosion is required. Exemplified at 2:53 (on the in-game timer).

This being said, nothing special about this floor, apart from the first chain reaction at 2:53 being frame-tight and not requiring any waiting, which is pretty fortunate (=> you have to do everything before as fast as possible and it just barely succeeds with a 0 frames margin, glad it works this way). Note: power-ups are usable as soon as you get them (as in `the exact frame you pick them up') as demonstrated here when grabbing a bomb power-up.

Floor 2

The only thing special about this level is one frame. Those coin enemies are likely the only RNG-free enemy of this mode, being totally regular in their pathing (mostly going straight forward and back). They often end up in those kind of pairs where they're separated by precisely one tile. Just like almost all enemies, entering the tile they're on means instant death (well, technically one damage, but since we have 0 hearts...). However in the case of those pairs, there is exactly one frame on which the front coin is outside a tile and the back one is not yet on it. At 2:50 this one frame is used to set a bomb between them.

Floor 3

Here the technique applied is exactly like the one behind runs like SNES Super Bomberman : become invincible (here through an armor power-up), auto-fire C for continuous explosion. This is seldom useful without an armor power-up though, since invulnerability from damage takes in this game only lasts 60 frames (compared to 600 with the armor). Hence the choice of going no-damage...

Also the first speed power-up is grabbed while waiting for the ladder, which will lead us to subpixel optimization in 2 floors.

Floor 4 : the Bomb Master

First boss fight, and not the easiest. All bosses in this mode have 6 hit points, get 180 invulnerability frames when hit, and have to go back to their original position at the start of their death animation (delaying the descent of the ladder). So in practice this means they should get hit as soon as possible, be bathing in flames every time their invulnerability expires, and be standing exactly on their starting tile when they die. Here the first statement isn't true since the boss could be led down 2 tiles as his first move, making him take his first hit 7 frames earlier. Still this fight is the one that provided the best RNG for later levels, so it was kept. This guy is the only boss whose attacks involve using bombs (and bouncing ones at that), so he tends to disrupt carefully timed chain reactions. Also it's hard to get him to stand still on a precise tile, which is problematic for the last hit.

Floor 5

Now that we have four bombs things are starting to get more interesting in terms of chain reactions. The enemies in this level are the bane of this TAS: those blue accordions have partly random movement, but their decision is somehow based on your position too. Here we get what is probably the best positioning we can hope for them.

Another thing maybe worth an explanation, since we got a speed power-up on floor 4 subpixel optimization starts here. The way speed works in this game is rather simple. Without any speed power-up you move one pixel per frame in the direction you're pressing, and that's it. Once you get your first speed modifier the `subpixel' comes in: it's a 1-byte value that increases by (32 * number of speed power-ups) each frame you're pressing a direction button. When it overflows, your next move will take you 2 pixels away instead of one. The thing to note here is that to increase the subpixel pressing a direction is enough, it doesn't matter if you're not moving because you're blocked by a wall or if it is not the direction you want your speed boost in eventually. That's why from now on everytime we have to wait we run into a wall for a couple frames to optimize this periodic 1-pixel boost.

Floor 6

First level with a kick power-up. It's very powerful because it gives you two options to get an explosion somewhere earlier than walking and setting a bomb there manually :
  • Either you set a bomb, let its timer run and kick it just at the right time to have it explode mid-course right where you want it (not actually used in the final run).
  • Or you can just set a bomb, kick it, and forget about it. You just saved yourself a full back-and-forth trip to where that bomb will end up exploding, and what's even better the actual explosion will occur earlier since the bomb timer doesn't stop when the bomb is moving.

Floor 7

First level with a power glove (is this exposition time or what ?). Not as good as the kick in a way since when you pick up a bomb it resets its timer (and the timer doesn't run when the bomb is in the air either). Still it lets you get things done quickly. Note: bombs will bounce off tiles with enemies on them, which we used here to reach farther tiles with our throws and redirect the coins.

Floor 8 : the Staff Master

One of the two nice bosses. What makes a boss `nice' to a TASer in this game is his ability to block bomb explosions, as strange as it may sound. Because if they can, they will, and almost every time they get a chance. That's pretty detrimental to their randomness. The process to TAS this boss can be summed up in one sentence: savestate, determine his next movement, load savestate, put a bomb to damage him and another one in his way. He'll try to poke the bomb in his way with his spear while the other damages him. That simple. If you can set the first bomb early enough you don't even need a second.

Floor 9

One of my favourite levels personally, because it has a little subtlety to it. There are two armor and one power glove hidden in this level, so you'd be tempted to believe that going invincible & perma-explosion would be the way to go, or maybe throwing some bombs in the ring. But if you poke around a little you may encounter the beautiful route used here, which is both faster and in my opinion cleaner.

The static blocks lighting periodically in this level are generators. If the number of enemies on the floor goes under a given threshold, they'll start respawning them. They won't have the time to do it in this run though.

Floor 10

Another power glove level, with more route planning and RNG. Those blue drop enemies move similarly to the blue accordions (read: in a randomly annoying way), but here again we get pretty much the best we can hope for.

Floor 11

RNG nightmare. Penguins are the worst enemies in the game when it comes to that (they are not only moving randomly but seem to actually try to dodge explosions to some degree), and those psychotic smiley faces aren't predictable either. The RNG (and consequently the route) used in this level can definitely be improved by more brute forcing. No telling how this would affect the other floors though as usual, which makes the process very tedious...

Fun fact: there's a remote power-up hidden in the block on the top right corner. At first we tried using it but it turns out with this number of bombs available and an open floor, well-timed chain reactions are just as fast as remote-controlled bombs, so it's not worth digging up.

Floor 12 : the Drunk Master

This guy is a joke, as we show right away by making him try to block the first explosion but fail spectacularly... Believe it or not but when I was a child I didn't get it was alcohol he was drinking and I ended up calling him `the milkman'. That's about how dangerous he is, even for a 10 years old standard player. The trick we use to lock him into perma-blocking bombs is very easy to realize even in real-time with a controller. Combine that with him systematically blocking bombs when they're in his path and you get the easiest boss of this TAS.

Floor 13

Another RNG-heavy level which goes decently well (45 frames are wasted waiting, but this is the best we could get). This floor is the first in which we get the power glove/remote power-ups combo, which is very potent since it cancels the waiting period normally implied by the throw's bomb timer reset. Too bad the remote isn't closer to the level start. The order in which actions are performed at the very end of the level (from 2:47) is different from usual as a consequence for maximum time-saving. 

Also we don't pick up the bomb power-up at the very end, not because it would lose time but just because it's not needed.

Floor 14

Perhaps the most frustrating bit of RNG in this run. Basically if the penguin on the left goes up instead of down at the start of this floor you can just throw your floor 12 boss fight and floor 13 route & RNG away and start over. Apart from that standard power glove level, go up while throwing bombs sideways continuously and done.

Floor 15

More of the same, power glove and throws, except in this one the focus is more on destroying the blocks in your way fast than on killing the enemies. One additional trick is used here: when you pick up a bomb, for a number of frames at the start the game considers it is still on the ground. Bombs on the ground act as walls. We use that to shoo away the blue accordions.

Floor 16 : the Old Master

Now here's a real boss. In normal play the main problem with this guy is that he's really good at dodging explosions, and also very mobile. This habit he has of jumping around also makes it very difficult to corner him for the last hit, and his overall high randomness is hard to deal with. As a result we couldn't get a perfect fight against him, missing possibly some frames on the first hit and one frame one the last (he has to move one pixel down to reach his ending position at the end).

Floor 17

Power glove and remote power-ups, no randomness at all, very straightforward level.

Floor 18

Last floor done using kick, with our flame level the best tactic seems to be carpet bombing. Little RNG involved in those enemies movements but nothing that caused too much trouble.

Floor 19

Power glove and remote from the start make quick work of this one. Also no RNG at all which is nice. We grab a speed-down power-up in the end because it's in the way, but since the only thing left is the last boss it doesn't matter too much (with out route it does cost one frame).

Floor 20 : the Dragon Master

What we originally thought would be the hardest boss of all turns out to be very predictable. He has two phases: during the first he's similar to the old master, dodging explosions and using flashy moves. But that's only for his first 2 hit points. After that he turns into a dragon. His dragon form is scary from a player's point of view, but as a TASer once you notice he always power jumps on your tile after taking a hit, it gets ridiculously easy. Also no ladder to reach in this final level, so the last input is a little earlier than usual, which is cool.

Final words

And that's mostly it folks. This was our first TAS attempt and it was really fun. There is work left undone though. Someone trying to improve this run would probably have to proceed like this :
  1. TAS the 3 first floors.
  2. Fight a perfect fight against the boss.
  3. Test the RNG on the next 3 floors.
  4. If the RNG wasn't good, redo step 2 differently. If the RNG was perfect, fight the next boss and go to step 3 until the last boss.

If the run is judged lackluster due to us not bruteforcing the RNG enough, we're ready to improve it some more. But we'd really prefer to start working on TASing the Normal game mode of this game, which shows great promise :) .

A couple screenshots to close the curtain :


feos: Accepting to Moons and publishing...

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