Ahh, sorry for not respond on sooner!! =o/
As for the 'bug', I remember him being able to kind of like... Surf on/over enemies. And no, no graphical changes, just wouldn't take damage.
I haven't had it happen nearly as often as before I posted, but every now and then boom, he'll be standing/running on top of enemies... Or into them, pushing them back against the edge of the screen or just going through a couple of enemies all-together. I think it might depend on the type of enemy... But I could just be putting pieces that aren't there together in my brain... Really not an every game kinda bug.
It's not a really big deal, the game is still definitely enjoyable, playable and beatable... But I thought I might as well bring it up. =oP