Unfortunately I got stuck. I beat the t-rex monster thing, accidentally fell down into the area before it's arena and ran into the checkpoint down there. There appears to be no way back out to the upper layer after the monster is defeated, unless there's a way to remove the stones blocking the passageway. Too bad, I was enjoying it! Also, having the ability to type in a number for the sensitivity rather than just a slider would be nice.
Depending on where you hit a checkpoint, you might still be able to progress. The shotgun can open up some new passageways (the green netting). If you post a screenshot of where you got stuck I might be able to help you out further.
The green netting was the piece I was missing. Thanks so much for the reply! Just finished up playing through and it was pretty dang enjoyable. I enjoyed how you structured the world with everything being in the same "level", but wrapping around in different ways after you unlock the different weapons.