You might need to go into further detail there.
If I am understanding it correctly.
At some point the beta for Sonic Rush (one video called it the E3 demo) leaked.
If you manage to glitch things then rather than display nothing the game will fall back to just being the 2d sprites (seemingly from Sonic Advance) rather than have nothing at all which is fairly common both as a general failure prevention and to have something to do while the 3d animators are doing their thing.
This fallback thing presents an opportunity and likely makes life a bit easier.
Cheats might be harder for this one -- I don't know if they can usefully write the 3d processor on the DS (
http://problemkaputt.de/gbatek.htm#ds3dvideo ) to mess up the model or animations, and while you could alter the binary in memory to do an in game command then if you knew that you would have. I would instead see about corrupting the model and/or animations (hopefully the nsbmd format by this point but it might be early enough to still be a custom or precursor format).
I don't know if deleting it or overwriting the file with random gibberish will do (might just crash the game) but worth a try. If not then a glitch is likely more that the animation at that point made an illegal combination and it stopped displaying it, that would be something to investigate there.
