Pretty cool game, glad that in this jam there was some old school shmup representation. They dynamic difficulty is a pretty cool idea although I don't know if it actually was changing much, although that could be just because I wasn't getting hit a lot. I think a score system would greatly improve the game if you were to decide to implement one as it would create more of an incentive to raise the difficulty, but that's just my thoughts. Good job, especially given you only had 4 days to work on this!