Interesting way to level up in this genre! I like it!
I tried all 3 weapons builds (I think getting double of the same is the way to go since you have a better chance for a good upgrade) but only machinegun seemed like a valid option, rockets were hard to aim , and shootgun... I thought it would be a multitarget weapong (piercing) but it just oneshoted 1 enemy and all the bullets were gone.
So! Machinegun it its, with this one I felt the best, it did what I expected it to.
Also thank you for the movement speed upgrades!!!
I think in such tight places player should be able to pass through enemies tbh, I got swarmed multiple times and I could not escape nor kill them. I feel like I should be able to decide 'Ok, I know I'm going to take damage goingh through them but this is the only way I can escape right now'.
Overall very good game with good upgrade system and very nice polish.