I played the web version so that might explain some bugs I experienced but for now here's my impressions:
It feels like a solid game, but one time I didn't bounce back from the slowed timescale and had to reload the page, and the progress bar at the end also feels kinda... janky?
But hitting enemies was very fun and satisfying, and the upgrade are meaningful and powerful. The only major problem I had was telling how much health I actually had left, which made it difficult to gauge how well I was doing