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

Submission #4136: WST & Got4n 's Genesis Sonic Boom in 03:03.99

Console: Sega Genesis
Game name: Sonic Boom
Game version: unknown
ROM filename: SBOOM.BIN
Emulator: Gens11svn304
Movie length: 03:03.99
FrameCount: 11025
Re-record count: 8225
Author's real name: Ilya Averkov & Got4n
Author's nickname: WST & Got4n
Submitter: got4n
Submitted at: 2013-12-21 23:36:41
Text last edited at: 2015-01-01 03:47:28
Text last edited by: CoolKirby
Download: Download (1400 bytes)
Status: decision: rejected
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Author's comments and explanations:

(Link to video)
Hi, guys! Here is the result of our cooperative attempt of improving emu2000’s old unsubmitted TAS of Sonic Boom. Sonic Boom is a brilliant Sonic the Hedgehog 2 hack, featuring a huge set of new moves, greater speeds and completely different tasks to solve. Whoever made this hack, is a genius. Also, it is an improvement of 1703 frames of DDRKhat run.

Actually, this TAS may slightly disappoint you. The stages are actually extremely long and complex, but they are pwned to the level when most time you are just watching the camera scrolling directly to the boss at maximum speed. If you would like to see a low glitch run of this hack, we advice you watching DDRkhat’s or Amarillo’s TAS.

Game objectives

  • Emulator used: Gens 11b + camera hack + solidity viewer + hitbox display + Sonic TAS tools
  • Aims for in-game time instead of real-time
  • Heavy glitch abuse
  • Slight luck manipulation


Level In-game time TASed by
Power Plant 1 0:32.17 WST and got4n
Power Plant 2 0:46.59 WST
Power Plant 3 1:07.31 WST

Stage by stage comments by WST

Power Plant 1

got4n made a TAS of this level and sent it to me. In my attempts to improve it I’ve found out a faster way to cause the horizontal underflow. got4n spindashed to the right, entered the wall and zipped left. I performed X-subpixel management and spindashed to the left without entering the wall, thus causing horizontal underflow 4 frames faster. In fact, on 19th frame of the in-game time Sonic is already waiting in the boss room.

However, faster horizontal underflow did not actually result in any improvement. Since the boss fight is triggered on certain camera position, performing the spin dash a few frames later (in my case) results in the camera stucking for a moment, thus, both methods of the level-wrap result in giving the boss the first hit at exactly the same frame. Finally we decided to choose my method of level-wrap, because it is technically a lot harder to pull off (trying to make it without looking at our input or knowing what you are doing is wasting time, beleive me).

The boss fight was completely done by got4n.

Power Plant 2

This stage was pure pain at first, because we couldn’t figure out emu2000’s route. However, playing this level just for fun many times suddenly resulted in discovering his route, which allowed us to switch to TASing it seriously.

It’s worth to mention that this level cannot be level-wrapped. There is some X space reserved for Sonic’s running-in animation, which makes it impossible to cause horizontal underflow.

The orbinaut in the end of the stage is so freaking big that it’s even not funny. Don’t you agree?

Power Plant 3

At first I expected this level to be easy. I was planning to take a boost in the very beginning, outrun the screen and just run to the end at maximum speed. But soon I’ve realized that it’s not actually as easy as it sounds. First, while running too fast, I’ve noticed that soon I reach a point where the terrain is not loaded yet. Despite being quite experienced Sonic TASer, I have to say that I never saw a thing like that. This is not the same thing as the one listed here: when you come to the mentioned point and wait, you can notice that your massively high X coordinate becomes very low in a moment. This means that the terrain in this level is formed dynamically as you run forward, which kinda explains how the hell this level is so long horizontally.

As I understand it now, the idea about TASing this level is to run ahead of the screen, but not too fast. Also you have to avoid spin dashes when being on screen, as they affect the camera’s normal move. Rolling helps very much in this level, as it helps keeping the horizontal speed equaling camera’s speed, while accumulating the on-ground speed, which can be easilly released at proper moment.

To control the camera’s position easier, I wrote a simple Lua script:

  local camera_x = 0
  local prev_camera_x = 0

  function refresh()
  	camera_x = memory.readword(0xFFEE00)
  	gui.text(10, 60, 'Camera advance: ' .. (camera_x - prev_camera_x
  	prev_camera_x = camera_x

During TASing this act, got4n constantly urged me, but I simply couldn’t make it quickly because of many things that were completely new to me in this act. In addition to the problems mentioned above, the speed of the fire in this act seems to be relavant to Sonic’s speed, and if you run too fast for a long time (for example, by taking a boost from wall ejection), fire accelerates too, and can kill you when you are waiting for the next dynamic block to be loaded, making it impossible to progress.

Stage by stage comments by got4n

Power Plant 1

yay, I made a first TAS of the level 1-1. It was pretty good overall but WST did a much better technic, and finally it decided to be the same time. We kept WST technic, because it was pretty good, and TAS-only I made the boss but there is slight luck manipulation for getting the shortest boss recovery frames.

Power Plant 2

Okay, that one was the REAL pain. I asked many TASers if they could help us reproducing the emu2000 route, because it was the best one, but no one could, even MarzoJr :/ . But, recently, WST told me he did find his route randomly. It was pretty cool, sadly, we couldn't level-wrap.

Power Plant 3

First, I think that it was very easy, but that level is pretty hard to TAS.

Overall (Got4n)

waw, the game is fucking hard to TAS because mostly everything is perfect!

Other comments

Suggested screenshot: frame 333 or 328 or 3906

Thanks to

  • emu2000 for his first TAS

feos: The run is good, but the hack was poorly received. People feel it was incomplete and had nearly nothing to showcase in a TAS except Sonic being offscreen. Rejecting.

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