It's really hard to believe one guy was behind the whole thing. Game is polished, the mechanics are tight, the bosses are fantastic, and some of them get extra attacks on harder difficulties. The movement is SO good, you always feel like you're in control (except for the occassional "walljump when I wanted to airdash", but you can disable walljumping (dunno why you'd want to, it has its uses)) and every single attack is decently telegraphed, and even when you're caught by surprise you can slow time and dash away and make it look like you meant to do that.
If you like skillful play like contorting an air dash to weave through bullets in slow motion while destroying the homing rockets coming your way, I don't think you can go wrong with this game.
It is REALLY short but for 5 bucks you're getting possibly the most concentrated, no-♥♥♥♥♥♥♥♥, action run n gun with slow motion. Get this immediately.