I think this game could benefit the most from added polish: sounds, particles, effects etc. especially to better sell the physicality and impact of attacks. The biggest weakness of the game comes from that physicality not being there, especially when your health goes down without you even noticing.
As it is I found I had the most fun when trying to run to the end past the enemies without fighting any of them since running past them untouched seemed to be the biggest challenge until the last level.
The overall feel and aesthetic of the game is really cool and reminiscent of those 90s shooters. With some extra polish this could be a game I see myself playing for fun from time to time.