Not bad at all for your first game jam game!  It would have been nice to have a bit more variety in enemies, but I understand how the time crunch makes that difficult.  The core gameplay was fun, and that is ultimately what counts at the end of the day.

This was also my first game jam.  I made a top-down zombie shooter called Sole Survivor where you only use the space bar to play.  I would really appreciate it if you tried it out!