In episode 51, when That Guy With The Glasses was ranting about Lost, that was actually The Nostalgia Critic wearing That Guy's robe.
That high-pitched ranting can only belong to the critic.- Doubtful. Ask That Guy can go just as loud, and has proved himself to be quite the Closet Geek.
The abuse That Guy's penis has gone through is not actually a plot hole.
He simply mentioned the events in the wrong order. When he attempted to have sex with the blender, he destroyed his penis, and then sacrificed its remains to the devil, who ate them. He would later replace it with a cybernetic machine gun penis.