Quake

The secret exit for Episode 1 is found in E1M4: The Grisly Grotto. This is a written guide + images to find the secret exit, a video clip is also provided at the bottom if you prefer.

Towards the end of the level you will use an elevator to reach a room with 5 panels on the floor with the Quake logo. Stepping on one will make the 2 dart traps shoot once. You need to hit all 5 panels, which will open two side passages in this room.



Go down into one of the passages (there will be enemies here if you didn't kill them on the way up) and press the button at the end. Now jump down to the elevator, go back up, and into the other passage to press the second button.



Now you need to backtrack to the big underwater area earlier with a sunken building in it. Follow the path the opposite direction of the elevator, back outside and into the water. Then you need to locate the big cave that has opened, it's to the right when you enter. It's a bit hard to see but in the screenshot, the cave is directly ahead (the passage on the right leads to where the elevator/buttons were).



Go inside this cavern and head up to find some items and a portal. Entering this will lead to the secret level E1M8 and give you the achievement.

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FOR XBOX PC PLAYERS:

Hit the ~ key and enter "map e1m4"

Now enter the usually "god" and "noclip"

Flyaround until you find a portal on the edge of the map. If you are looking at the silver key on the dock over the water, it's just to the left of that through the wall. You know its the right room if the only (legit) way in or out is a small water hole. turn off "noclip" and the achievement is yours.

Here's a guide to finding the secret exit and getting the achievement Vertical Vengeance, text is below the video guide


2: hit level select and select e1m4 the grisly grotto on easy difficulty

3: right off the bat go through the big doors and drop down taking the door to your left

4: grab the suit and drop into the water taking the right door under the water and resurfacing picking up the super nail gun

5: kill the enemy's in this hallways towards the elevator at the end

6: at the top of the elevator kill the two knights that are there and go to the left hitting the switch that opens the big door

7: clear this hallway on your way to the silver key at the end of the platform jump off and head forwards through a hole in the wall if you missed the silver key

8: once you get to the door with the silver key head left and follow the path to the next elevator killing any enemy's you come across along that path

9: once you get to the top of the elevator dispatch the two knights up there and then hit all 5 switches on the floor every switch you hit will shoot spikes from the wall then after that two doors will open on either side drop down and hit the button on both sides

10: now just back track through the hole in the wall under water and head to the right there will be a cave that opened underwater swim up and theres the exit