I really liked the minimalistic visuals.
I just feel like this genre needs more content to be fun. There is too little upgrades to choose from right now, making the game repetitive too soon.
It also doesn't help that the difficulty seems to be constant through the game - I rather deceided to die voluntarily around level 14. If I was defeated by the ramped up difficulty, I might have been motivated more to try again.
The "what if" encounters were refreshing part of game.
Personally, I didn't like the click to slash/shoot controlls - it just makes my wrist hurt. I think hold LMB to keep shooting in some intervals would be more comfortable.
Overall - I think the game has pretty good cornerstones set and with more content and threat I will happily play again.