Yeah, the fullscreen wasn't working on the web version so I ended up just disabling it... the downloadable one does have fullscreen, though. I see what you mean about the knights now, I think the bigger issue was that I didn't really make it clear that the rusty knights weren't designed to be faced head on and were meant to be snuck around... it looks like you figured that out for the tower area at least but that first fight with one was definitely rough. Maybe I should have made them immune to damage entirely?
That one collision bug ~15 minutes in is pretty odd, I had something like that happen once but I thought I'd fixed it. It seemed like it happened because of how fast you were falling so maybe adding a terminal velocity would help.