So, I think my biggest complaint against this game is that the way to face off against the final boss wasn't clear enough. I was at stage 9 and difficulty 40 when I realized it was there, so I finished the game at a time of 29minutes, 37 seconds, with 138 items. This wasn't even that much of a problem since I'd only somewhat gotten bored, but it meant that when I did face the boss my hp never got a dent even when I just stood there doing nothing.
That said, I think this is the game entry I'd most like to see go somewhere after the jam so far (for context, I've got 19 entries left to try). However, I think the balance needs a lot of work. The game was hardest right at the start, mainly because of needing to find ways to gain more time before the enemies started spawning enough. After 2 stages I didn't need to care anymore and after 3 stages I stopped caring much about hp either.
Still, most of the elements are beyond what is typical of a jam. The only other thing that bugged me was the ranged attacks being a little too hard to dodge at the beginning of the game. I would've preferred they speed up later.