Endgame spoilers:
I'm stuck in the mountain where you have the two bridges opposite each other. I know earlier posts have said you have to get back to the original (blue) side once you get over to the yellow side, but there doesn't seem to be a way to complete it on the blue side to allow the yellow bridge to cross back over? Additionally, how does the door that seems to be the destination for the bridges open? Once the yellow bridge hits it, will it open or does something else trigger it?