I agree with Kemsou, the game is pretty cool, with juice, cool graphics and fun gameplay, but it's quite ruined by the balancing and pacing : levels are pretty long, with quite few enemies, but every hit you take costs so much that it's almost impossible to finish the game with al the upgrades.
I finally got the shield upgrade hoping it would allow me to avoid getting hit, but it's almost unusable because you cant shoot and shied at the same time, and enemies constantly shoot so there is no windows of opportunity to switch weapon and attack, it's better to just stay with the gun and kill them as quickly as possible.
I'm a bit sad, because this game has a lot of great things in it, and it's really close to being great... I'll check the post jam patch whenever you release it !