Thanks. Gave it another shot. Not bad, the bosses have a little bit of that "Nintendo hard" flavour to them, which I assume is what you were going for. Haven't beaten the third boss yet.
First boss had a couple issues, I think - one that made it maybe unintentionally challenging, and one that made it "cheesable", which I'm not sure if that was intended. The cheesing - could walk right up, and keep kicking until it telegraphed the hammer swing, had just enough time to walk out of the way, then turn around and repeat. I assume that's intentional given how tight the timing was, but I was able to pretty much repeat that indefinitely until I won. Maybe the attacks didn't randomize as much as intended?
The challenge with the first boss is that when it's bouncing around, it's not obvious when it's coming back in for a landing, so you can think you're walking under its bounce, and then it just ends the bounce midair and reappears on top of you.
Second boss was solid, good telegraphing of attacks - pretty sure all my issues with that on were just my own skill and getting my fingers tangled around the controls.