Absolutely wonderful - the art is superb, with a fantastic tileset and phenomenal animation for the player character. Just a joy to watch!
Music and sfx are perfect, and really fit the tone.
The world feels huge, and is great fun to explore. Having a degree of choice in where to look next felt great :)
Gameplay is challenging, mastering control of momentum proved essential and led to a very satisfying feeling when I was able to pull of a tricky section. The gaps between checkpoints work really well, forcing you to play well consistently for an extended section. That said, I'd love an alternate game mode with unlimited restarts from the last checkpoint - it's definitely a little tricky for me!
Fantastic game all around, I love how far you've been able to push the limits of PICO-8 :)