Thanks! I'm glad you enjoyed it for the most part. The video with reactions also helps me see some parts of level design that might be confusing.
The Different barrels do work, but currently don't look any differnt ingame, I intend to fix this, but currently it's pretty low on the list of priorities.
The level 4 stages are pretty difficult, took me a few tries to beat that first stage when Faxdoc first made it. The trick is to jump, then while you are mid air, shoot the hook to one of the sides, and move your mouse in that direction to get some extra power.