It's a fun shooter reminiscent of asteroids with powerups and multiple enemy types.
So... Go... Play... now... :)
http://js13kgames.com/entries/radius-raid
and yes there are a bunch of other entries to the contest off this page http://js13kgames.com/entries

That is impressive! In just under 13k, Radius Raid provides all of the following essential game elements:
My only beef is that the difficulty doesn't ramp very quickly. 7 and a half minutes in, I was in very little real danger of losing. Still, 13k!