I thought the camera work was really great here. Things felt really natural transitioning from the player-focused cam to the fixed or axis-aligned modes. There was some jittering artifact on the player sprite for the player cam, but otherwise great!
Movement all felt good. It did feel rather difficult to make successful strikes on the flying enemies with such a limited attack range. This could probably be made a bit more lenient. Spike insta-death also felt kind of brutal compared to how many hits you could take during regular combat.
Boss combat felt fair, though I usually didn't have enough biscuit resources to buy anything by the time I made it to the first boss. Since the player is able to warp back to spawn anyway, maybe the shop could just be a permanent fixture there.