First: put some Soundeffects on the Picking up of items - a Bling on the coin, a Swoosh on the potion and a Bluarb on the heart - you know what I mean. Other to that - I can literaly see this be part of a Bigger game 1 to one as a Section where you need to get out of a canyon you dropped in. Let the falling big rocks be half the size high but stay in the area to change the world so the higher the ground gets the harder it gets to avoid. The Jump could use a little more snappyness - maybe crank up the gravity so you fall faster because it feels floaty as is. Cisualy you could put some glowing or some slow moving fog in there, or some particles thet rissle down from the top to make i make the feeling more indepth.
PLease don t see this as a critic, I like the game instantly and had my 15 minutes of great fun with it! thats my highscore so far xD
