It looks like I'm using Ruby + Gosu again! Probably Pixen for graphics (or just drawing primitives), plus sfxr for audio. No idea how music will work.

All that said, I'm in for the Jam, not the Compo, so I may also dig around in opengameart.org if I need extra resources.

There's a small chance that I'll make a last-minute swerve to using Unity instead... but I don't think so.