For this Game Jam, instead of coming up with game ideas myself (the kind of games I like
are pretty niche) I implemented solid mechanics others have already
thought through.
I built 'Planetary', a physics based game utilizing Box2dJs, and a
simple Shoot-Em-Up 'Telemachus'.
PLAY Planetary

Telemachus takes two and a half minutes to play through. Planetary is
round-based and typically takes a couple of minutes to complete.
PLAY Telemachus

Both games require a modern browser. Chrome4+, Safari5+, IE9, Opera10+... enjoy :)
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* code repo is linked on game page (github; license MIT)
* artwork is CC attribution