I can't blame you for trying, it was a good idea but...
1: Its rushed, I'm sure you know this but its clunky and honestly I think you could of done much better (As this looks pretty good as it is).
2: The "Help Markiplier" level is slow, dark, and the controls are way off. Honestly I would of loved it if it had been a bit better thought out. (Maybe a top down of you running around fending off ghouls with flashlights?)
3: The Septic Eye... I thought at first "Whoa a run around shoot em' up boss fight!" which I would of loved if it was possible to dodge 50% of his attacks. The reason its hard comes down to 3 things. First is the level size compared to the boss and his attacks. The second is the size of the bosses attacks, change attacks rather than just jumping size with the same attack pattern, I keep getting hit with walls of attacks I can't dodge. Third is the character size, I have no feeling of where he is because hes so small which makes dodging hard to begin with, an easy fix for this is for the camera to follow him around.