Got stuck on the part with the yellow & blue triangles. I know the yellow one (a spike?) kills me while the blue one does nothing, but going to the right does nothing. There is also an invisible block near the right of the floating platform in the same room. What am I missing? Also...
Spoilers ahead!
... from what I gathered, the game's controls are dictated by the letter the action starts with. A for Attack, R for Right, J for Jump, and L for Left. I think the key to Enter is either E or - well, enter.
EDIT: It's E to Enter.