This guide explains how to get into the eye room step-by-step.
Guide to Getting into the Eye Room
To start, beat the first level (or load a save) and make sure you're here.
Next, you want to go to the area with the dead people.
The wall that the guy is leaning on is solid, so wall jump and get to the balcony with the door.
Walk through the door and there you are, the eye room.
The red door thing will show some words when you go through it, so just enter the door a bunch.