Really awesome! This was a lot of fun to play, simple but effective. It felt like a very substantial game, and is fantastic for a game jam submission. I think the balance could do with a bit of work, sometimes it's too easy and sometimes too hard (mainly the scaling of the enemies). I think this might be a result of the randomness of the upgrades (good idea, sometimes a little difficult to tell instantly what the effect was but the cumulative result was very satisfactory). A couple of maybe bugs: the shooting was a little off centre, which is a pain in a game that requires accuracy, and sometimes the closeness points didn't seem to be given even if I was right next to the enemy. Overall a really fantastic game that I enjoyed immensely, you should definitely continue development!