Is the theme just that it is a GameBoy Color type of game or is there a specific theme to the gameplay that hasn't been announced yet?

Actually, I think the only issue is Game Boy Color, because apparently, in the other Game Jams it was the same. 

PS: I'm looking for a team, if you're interested, write to me at yex_da_fox in discord

Yeah it's just to keep it to the gameboy color resolution/limitation. This is a monthly game jam and this is this month's gimmick.