Level 14: Genesis
Back to Final Doom
From the Start take out the Hell Knights and clear out any other enemies from the side windows. Take the path to the south and from the doorway clear out the Revenants, Arachnotron and Chaingunners.
Once it’s safe to proceed head down the steps and go through the opening to the west. Head up the stairs and dash across the gap to the walkway. Drop down on the west side to the blood waterfall and lower the first step. This will reveal a teleporter that takes you to Secret 1 where you’ll find Blue Armor. Head up the steps and a door will open back out to the main pool.
Head up to the walkway again and this time follow it around to a room to the north with the tan walkway. Walk across it to the Invisibility sphere and the walkway will lower. Take the elevator up in the corner and clear out all the enemies. Some of them will fight among themselves.
Head around the walkway and press the Switch on the other side. This lifts up the center walkway. Dash across and head back. A bridge to the Yellow Key will also have lifted up but there’s an Arch Vile on the other side. Take it out and then grab the key.
A second Arch Vile will also be running around. You can probably find him in the main pool close to the Yellow Door. Head up to the main walkways and open the wall to the north. This is Secret 2 and takes you to a ledge with a Backpack.
Drop down into the circle in the main pool for Secret 3 with a Megasphere. When you drop into the circle it will lift up so you can get back up.
Open the large Yellow Door and blow up the barrels and the Chaingunners. Take the teleporter up to the ledge above and follow it around to the Exit.