Definitely one of the most cohesive entries in the game. Such a well polished game for the limited timeframe. I'm super impressed. I love the UI, the slight grittiness of the art, atmospheric music, the camera shake, all the various upgrades you managed to slot in.. You've basically made a prototype for what could be a commercial game.
Now because it's very good and perhaps the best game of the jam, I will chime in with my criticism >:) I agree with Dave, I think SFX was the weakest part and the game ramps up too slowly. I want more bass on those bullets, more feedback on hits. I love when wave games go absolutely bonkers, and when the upgrades are visibly OP. The upgrades in this game feel subtle, and hard to notice. For a game jam I think it's important that you showcase the potential of your gameplay as soon as possible, even at the risk of creating balance issues. Examples: Make bullets much larger, make bounces noticeable via trail effects, add more contrast on the black hole and ya know what make that thing bigger too. More enemies with stronger upgrades to offset the increase in difficulty.
Now here is where I have to remind myself that it was literally a 72h jam. There's only so much you fit into that timeframe! On some games I may omit criticism, because I see how the timeframe affected them.. but for yours it's so good already that it's easy to forget you did this in a weekend haha.