This is genuinely awesome. Very difficult but an incredibly fun and rewarding set of mechanics to interact with.
Honestly, the difficulty curve was almost spot-on for me, especially in W1. Very difficult but the challenge feels very surmountable, and almost always fair. There's a noticeable jump from W1 to W2, but I think that lies more in that the slimes are much more finicky than anything in W1, and the movement system makes that level of precision inconsistent (most visible in the moving slime in screen 3 and the first slime of screen 5).