The portal behind the gate is not disabled if the gate is undefeated. Video evidence: I tried leaping the castle of Sparta and encountered an invisible wall. Will try other levels and update if any are possible.

During a speedrun attempt I clipped through the railing after flying with the pelican. Doesn't seem to have any uses but a funny moment none the less.

Video: Clipping through near the end.

I got a sub 34 pace run dying by a double Out of Bounds clip during the Rock Paper Scissors stackbattle. First time I quit and reloaded and it happened again. Not usefull but odd to say the least. at the end (of course) around 33 minute mark.