CAN WE USE GB Studio ???
Yes, but only if your game is compiled for GBA using gbsenpai.
(your submission must be a ".gba" file, not ".gb" or ".gbc")
what about "converting" .gb file via goomba to make it gba?
Nope, we decided from an early stage that wrapping a non-GBA game in an emulator would be against the spirit of the jam.
gbsenpai is allowed because it's an engine rather than an emulator - the games are compiled to native GBA code and run at native resolution.
thanks for clarifying