TASVideos

Tool-assisted game movies
When human skills are just not enough

Submission #6770: link_7777's NES Eggsplode in 02:38.07

Console: Nintendo Entertainment System
Game name: Eggsplode
Game version: USA
ROM filename: Short Order + Egg-Splode! (USA).nes
Branch:
Emulator: Bizhawk 2.4
Movie length: 02:38.07
FrameCount: 9500
Re-record count: 4762
Author's real name: Phillip Grimsrud
Author's nickname: link_7777
Submitter: link_7777
Submitted at: 2020-06-04 22:26:55
Text last edited at: 2020-07-30 04:02:17
Text last edited by: Spikestuff
Download: Download (6107 bytes)
Status: published
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Author's comments and explanations:

Eggsplode!

Eggsplode! is a power pad game that came on a combo cart with Short Order. Step on the bombs that the naughty fox has placed before they Eggsplode!

Encode

Game objectives

  • Emulator used: Bizhawk 2.4
  • Beat stage 6 (60 bombs)

When I first picked this game up and started looking at the win condition it looked like 0x4B was the stage counter and it looked like the game would soft lock after 255 stages. After putting more time into it however I discovered that 0x4B is the number of foxes on the stage. There is no actual level counter, the number of bombs in the stage (0x4D) starts at 10 and increases by 10 each stage up to 60. The other difficulty parameters are derived from this. Stage 6 has 60 bombs and is the most difficult. This 6th stage with 60 bombs repeats indefinitely. It was a bit hard to test because they stored the score directly in the nametable, but the score just wraps if you max it out and it doesn't break anything.

Controls

  • 1-12 stomp on the corresponding bomb

RNG

The RNG (0x55) in this game is pretty well done. The function that advances the rng does 0x55 RNG next = (previous << 2) + previous + 0x11, but this is not just called every frame, it is also called in the wait loop at the end of each frame. Since the outcome after each from depends on how much other code executes that frame this means it is difficult to manipulate the RNG for a specific value, but easy to influence it. Just pressing some buttons influences the execution, even if you aren't actually hitting anything. This is used frequently to try to spawn the bombs as quickly as possible.

Strategy

From a tas perspective once you've influenced the RNG the game becomes trivial, just press the button corresponding to the bomb location. This is done through the 6 stages (210 bombs total)

Unused Game elements

There are a couple of things not seen in this run, namely that the character that holds the sign can walk across instead of the fox and no bombs will be planted during this time. This mechanic is not useful and easily avoidable

Also the chickens can lay eggs which you can see at the end when stage 7 plays itself out. If you crack an egg you lose a bird (life). The game is over if you lose 2 lives or a bomb explodes.

Improvements

  • You have to wait for the bomb crumble animation anyway, but I tried to make the wait time between animations as small as possible. In some cases all of the foxes are between bombs and it takes a few frames for one to come in range. It may be possible to spawn in a different order in some places to reduce this slightly, or possibly allow multiple bombs to spawn before crushing them. I think there could be a few frames shaved by spending a bunch of time messing with it, but probably not too many.

Thanks to:

  • The TASMania team

Screenshots:

13, 700, 9786, 11023

Blaze's comments

I discovered that the input end can be extremely early in this game. The game uses a queue system that can hold up to 255 inputs, and while you're crumbling a bomb, it doesn't deplete. Thanks to link for finding the RAM addresses for the queue array and the queue size.

I ended up saving 1101 frames off the end of level 6 by filling the queue nearly to max and getting lucky enough for the bombs to be planted fast enough that the queue didn't run out too soon.


ThunderAxe31: Judging.

ThunderAxe31: File replaced with a 1102 frames improvement.

ThunderAxe31: Even after deeper researches, it seems to me that beyond stage 6 there is no increase of difficulty in any form. So I consider this movie to be complete.

Execution seems good, but gameplay resulted aesthetically plain, and the audience reactions were overall not nearly enough welcoming.

Accepting for Vault.

feos: Pub.

feos: The manual doesn't have ! when spelling the game name, even tho in arts it is there. Inconsistent, so it's up to the publisher, and I prefer manual's text.


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