Great game, but has underlying longevity problems. The first 15 waves are absolute boring fodder once you get to the point where you know what the powerups are. I'd do something like Ultrakill's Cybergrind wave system, where once you reach double a wave milestone, you can start at that milestone instead.
Also, losing your parry when you get a powerup is really annoying. It's your only defensive mechanic, and the game greatly relies on you having it. Otherwise you can get put into undodgeable situations and either waste your powerup or just die.