I've checked the latest version, and there is indeed a is_gba variable now. Thanks a lot for the heads up, I'll definitively use it to add GBA support in a future version of the game :)!
You could also add support for the SGB2 using a similar method to Tetris DX to detect the SGB2.
Yes, I do plan to try to add SGB2 support too in the future :)
(first I need to get an actual SGB2 to test if everything is working well :p)
