My main issue with this game is how the jump height varies based on the character's momentum. I don't think this is a bad idea on its own, but there are multiple places in the levels where I was expected to build up walking speed and jump around and back onto a solid platform directly above. These jumps are made frustrating by how the momentum is lost if I change my direction before jumping and how there is often very little room to build up some momentum on the platforms I need to jump from. The slopes also feel a little awkward to move around on and I found myself getting somewhat stuck on them.
The shield and key items seem like they could be made more convenient if they were automatically used. I haven't encountered a reason not to immediately equip the shield when getting one, and it would save a little time if the keys were automatically consumed when trying to enter a locked door.
I encountered one issue with the wall collisions on the cave portion of Level 1-2; I jumped left and over the wall as the moving platform brought me to this area and found myself trapped within the walls, unable to escape.
