Fun game!
I really liked the art, I thought it was really cute.
I think the different guns could be more unique (or more balanced). The sniper was just by far the worst weapon in my experience, the only upside is that it doesn't give carpel tunnel. Maybe the sniper could have a larger range (could look further away).
On the note of range, basically none of the enemies posed any threat since even the or shotgun far outranged them already (which made the sniper even more useless). Maybe make them faster, knockback resistant (knockback also made the pistol really OP), shoot faster, etc.