The two planks under the valley took me some time to figure out how to get across the river without dying. The "rock with instructions" blends in so well that I didn't notice them at first, maybe make them glow or something to be more visible?
The game only has smooth locomotion which made me a bit sick, but I guess you have to remove teleportation as that would make the challenge too easy.
The lava part is a bit difficult for me. Am I suppose to leave some of the planks there? I can't get all planks back in time.
Anyway, great game and good job for finishing it. The SFX are really good.