Submission #6842: Lobsterzelda's NES Battletoads "warps, 2 players" in 10:40.61

Introduction:

Plot:

Controls and Mechanics:

Submission Format:

Common Tricks:

RNG Manipulation

In Battletoads, RNG is stored in 4 memory addresses, which are combined several times with the exclusive or operation every frame. Additionally, certain other memory address values also alter the value of RNG each frame. One of these addresses is the address which stores player 1’s input on the last frame. Each of the 8 buttons is given a value between 1 and 128, which are added together to produce a single value that represents what buttons were last pressed. This value is then used to alter the RNG on each frame. Because of this, by pressing select on random frames and a random number of times, we can alter the game’s RNG to work in our favor! Doing this, we can manipulate favorable outcomes without losing any time whatsoever.

Cutscene Manipulation

The cutscenes between each level can generate a different number of lag frames based on the value of RNG. Thus, by doing the RNG manipulation described above, we can save 1-3 frames off of the number of lag frames between each level.

Combining Lag Hits

Certain finishing moves that the toads execute generate multiple frames of lag. However, if both toads perform their finishing move at the same time, then only 1 finishing move will cause lag, but both finishing moves will damage enemies! (for example, if a move takes up 8 lag frames, if both toads do it on two enemies at the same time, then only 8 lag frames will pass, but both enemies will be hit. This is faster than if the toads hit the enemy on different frames, which would cause 16 lag frames to occur instead).

Jump Boosting

In 2D levels, if you are jumping up and pass a specific spot near the edge of a platform you are jumping towards (while below the platform), then the game’s collision detection will cause you to get boosted up so that on the next frame you are on top of the platform. This is able to save about 3-4 frames per jump in sections where this trick is used, which can add up to some nice timesaves in the long run.

Passing Through Checkpoint-Walls

In levels 4 and 9, if you alternate pressing right and pressing nothing every other frame while a checkpoint-wall is to your right, then you can actually clip right through the wall (the same technique works with pressing left when a wall is to the left of your toad).

Left+Right Simultaneously

In 2D levels, a toad’s x-coordinate determines how far to the left or right they are in the level, and the toad’s z-coordinate determines how far up or down the toad is. The y-coordinate is not used in 2D levels, and instead is a fixed constant which doesn’t change. However, if you hold both left and right on the same frame in a 2D level, then the toad’s y-coordinate will start to increase. This causes the toad’s sprite to rise on the screen. Collision with certain objects rises with the toad, while collision with walls, floors and other objects remains in place. If the toad’s y-coordinate gets past 255, it will wrap around to 0, which will cause the toad’s sprite to suddenly fall back down to a normal level. This trick is often used to force the screen to scroll up, or to reach certain locations sooner than would otherwise be possible.

Timesave Table:

Level-By-Level Analysis:

Level 1: Ragnarok’s Canyon

Level 3: Turbo Tunnel

Level 4: Arctic Caverns

Level 6: Karnath’s Lair

Level 8: Intruder Excluder

Level 9: Terra Tubes

Level 10: Rat Race:

Level 11: Clinger Winger

Level 12: The Revolution

Beginning

We Need to Talk About the Red Faces...

LDA RandomValue_2
AND #$07
SEC
SBC #$03
STA Objects_Z_speed,X

Red Face Optimal Script:

Ending

Level 13: Armageddon

The TASing Process:

• Levels 1, 3, 4, 6, 8, 9, 11, and 13 were copied directly from my old 2P Warps TAS
• Level 10 was copied from my new 2P Warpless TAS
• Level 12 was initially copied from my old 2P Warps TAS. Then, I used my lag-reduction script on the red faces section to add input that would minimize lag. Additionally, I had to redo the final climbing section of the level after the fourth red face, since this section has a variable amount of lag which is almost impossible to sync.

Potential Timesaves:

1. Level 4 Skip: Theoretically, it should be possible to spawn a warp portal in level 3 instead of the level-end object, which would allow us to warp directly to level 5. In level 5, there is another glitch that works the same as the level 3 jet glitch, which would let us skip to level 6 in just a few seconds. Thus, we could completely skip level 4, and would save over a minute compared to this TAS (which would easily push this TAS to sub 10 minutes)!
   
   Unfortunately, while I believe I have come close to figuring out a way to get the warp portal to spawn and activate, there are a few things that just barely don’t work, which prevent this trick from being possible. If I were to describe all of the details of how this trick could work and what’s left that I need to discover to actually make this trick work, then this submission could easily be about 50% longer than it currently is. Fortunately for the interested reader, I have included a link to a series of forum posts I made in the Battletoads game thread which describe my findings: Level 4 Skip Information
   
   It’s worth noting that I have set up a $50 bounty that lasts until the end of 2020 if someone can find a way to get this skip to actually work or if they can provide me with information that leads to me being able to figure this out. Some of the things I need don’t require in-depth knowledge of how the game works, and could be found by doing repeated trial and error. Will you be the one to discover the most elusive glitch in Battletoads history? Only you have the answer to this question!
2. In the arctic caverns, I could save between 5-7 frames by using a trick where you pause and unpause the game to maintain your speed after changing directions while falling. To see what this trick actually looks like, you can examine the video below:
   
   
   
   (Link to video)
   
   The main reason why I didn’t include this trick in this TAS is that I didn’t know about it until after I finished TASing level 4, and in the section right after this trick is used (where you need to clip through the slope), there is a huge amount of lag, and the position for the optimal clip is very difficult to get. Also, the further apart your toads are, the more lag you generate, and the number of lag frames you get here is very hard to manipulate (furthermore, doing this trick seems to make one toad get slightly further ahead than the other toad compared to not doing this). In fact, it took me 2 days just to TAS these 4 seconds of gameplay the first time! As such, I am leaving this as a potential improvement for the next brave spelunker who wants to explore the world of creating Battletoads TASes.
3. In level 6, if entertainment value were completely ignored, it would probably be possible to save between 5-20 frames by making the snakes turn their heads slightly sooner. When the snakes turn their heads seems to be based completely on camera position, so you would have to move in a much less entertaining, more deliberate pattern in order to get this timesave.
4. In level 9, it's possible that some lag caused by enemies while swimming could be eliminated, which could save 10-20 frames. However, it's oftentimes not clear what lag is caused by enemy movement patterns which are RNG based and what lag is caused by other factors such as being out-of-bounds, so this isn't quite as simple as it sounds.

Special Thanks:

• Koorvex: For discovering an old, long-lost TAS of Battletoads in a collection of files given to him by his friend Daniel which had a faster level 10, which showed me how to save 2 seconds in level 10.
• DyLaX: For creating the long-lost TAS which had the improvements that I used in level 10.
• Daniel: For giving his friend Koorvex the long-lost TAS with the level 10 improvements.
• feos: For discovering many of the glitches used in this TAS, and also for creating the route for several levels.
• Alyosha: For creating an optimized Battletoads WIP that helped me learn how to TAS Battletoads in the first place.
• MESSHUGAH: For helping to figure out how the level-end glitch in levels 3 and 5 works
• Koh1ds: For discovering many of the glitches and timesaves used to make this TAS as fast as possible.

Concluding Remarks: