Great little game for your first Jam, well done!
I certainly think your game has a lot of potential- with a bit more time (and of course, practice!) - with some power ups, effects etc., this could be a very nicely fleshed-oout game! - More than anything I look forward to seeing what more you make in future jams!!
The only thing though that it felt was really missing, was just the score on the retry screen, so I knew exactly how badly I did! XD