[9-21] E3M4: Satan's Dark Delight

After you activate the bridge to cross over to where the rocket launcher is, keep going straight to the other side. Once you turn left and head down the ramp into the room, look up. You'll see a ledge just above you. To get up there, take the *other* ramp out of the room. On the right side of this ramp, against the wall, you'll see what looks like blocks. Don't worry about them being blocks – you can actually just walk right up them as if they were stairs. There are some nice pickups waiting for you up there.

While you're riding the platforms over the water chasm, you'll pass several ledges. Keep an eye out for one specific small ledge – it's the last one you'll pass before the moving platform heads towards the area with the crushing walls and the button to raise the main bridge. Make sure to jump onto this small ledge. Walls will open up, leading you to a ton of great items.

This is a follow-up to the secret in step #2. Inside that secret area, look for the light that's farthest to the left, near the base of the wall on the left side of the room. Shoot it, and a small closet will open up, containing a 666 Armor for you.

After riding the platforms and raising the bridge to get to the other side of the water chasm, you'll enter a rising platform. This will take you up to a small, square room. Notice that one of the six lights in this room is yellow, not white. Shoot that yellow light, and it'll open up a door to the Invulnerability power-up.