Well my feelings are mixed. I didnt play that much but theres my opinion:
1. Laks any response. I had a bit of trouble understanding if i have ben doing any damage or am doing something wrong. Make enemies flash when they get hit or something cuz sound is not enough.
2. Theres no instructions. I had some trouble understanding that map thing screen, then i neede a bit to realize that theres a "currency" that you spend on upgrades, like its meter is far right and left to the screen of course im gonna miss it.
3. Doesnt really feel good to play. Weapons feel underpowered and confusing even though i have seen only three: Pea shooter-blaster, stabby stabby glowy stick and the worthless bazooka that destroys walls only when its bothered to. Add some camera push back when you shoot and make enemies get pushed away when hit.
4. Boss is kinds boring. I have only seen 1 boss but still. Hes just a white version of the player with the sword, he doesnt even try to attack you that much, instead he teleports and instantly hits you with nothing you can do about it. Make a mark of where he will teleport and a little delay beetwen his teleport and attack.
All and all the game isnt really bad, theres just many little problems that form into one big one.