9 Intense Video Game Secret Levels You Can't Handle

7. Sacred Ground - Cave Story

Purpose-built to be the kind of thing you need to keep in mind across an entire save file, getting into Cave Story's Sacred Grounds requires a ton of planning and forethought.

The entire breakdown of what you need to do ranges from skipping specific upgrades, acquiring noteworthy items and rejecting one character's offers to help, all at key points in the story, but following this you'll open up a new path during the final escape.

Inside Sacred Grounds (which fans have nicknamed Hell, because it really is disgustingly unforgiving) you can get a chunk more character building to ease the pain, but you'll also have to put up with a LOT of trial and error game design.