Nice game, I liked it!
The character felt good to control, both with moving and shooting, and while the graphics are simple, I find them cute and I like them.
I don't really like how stunned enemies always stay in their place, since by day 15+, the whole battlefield is cluttered with them and they get in the way. Maybe have them despawn after a certain time or at the end of each day? Finally, it unfortunately seems like healing yourself and your friends doesen't drain your money.
Still, I like your game and I hope you continue with game dev!
Ironic how the main character doesen't have a hat in a game called hat fighter... Maybe that's why all the hatted folk are trying to kill them? :O