Hallucinations (Spoilers!)

[Apjjm]

Why the sewers isn't hard at all, I barely even had to TRY

Doing it normally is easy. Doing it as fast as humanly possible is a lot more difficult thanks to a rather nasty set of jumps that need to be performed (note again, quickly). If that brute wasn't a hallucination, one would have to add some enemy dodging right at the start of the area which looks to have incredibly tight timing.