The upgrades were fun and rewarding (Especially getting multiple movement based ones like the office chair and zooming around the levels), and the time limit for each level adds a risk/reward element in terms of how many upgrades you aim for.
For me, the biggest problem was the lack of feedback to the player. The UI elements for health/stability were so small and out of the way I barely looked at them even though they contain necessary information. And there was no indication when I'd been hit, when I'd hit something or when my dash was ready to use again. Even something as small as my health flashing when I took damage, so I could see in my periphery that I'd been hit would have gone a long way in my opinion.
Definitely more positives than negatives though and super impressive considering the time constraint. The movement was smooth, the gun looked great (With the player pumping after firing being a really nice touch) and the levels were bizarre and interesting. Really enjoyable experience and a creative take on the theme. With some post-jam polish, this would be a really cool game. Awesome job guys.