There's a #dreamcast #gamejam in December, early starts are allowed. Some prizes available and the possibility of being included on a physical compilation disc.
DreamDisc '24
A game jam from 2024-12-20 to 2025-01-04 hosted by PsyOpStudios. The full rules as well as extra info can be viewed on the OrcFace website . Welcome to DreamDisc '24! DreamDisc is the premiere game jam for Dreamcast...
itch.io (itch.io)
Never programmed for the DC before? There's #raylib support via 'RaylibDC' if you know C, or a cool looking lua game engine https://antiruins.com/engine