This is the fastest route for The Bunker Any%. The first route used a sandbag to clip through the wall outside of the first room, then use that prop to prop fly from the map load area to the very end. It was obsoleted by the route below, but has been archived for historic purposes here.
Example run of this route here.
Route[]
The goal of the game is to escape the bunker. Using the regrab glitch, this can be achieved extremely quickly. Intro skip can be unlocked by beating the game once, therefore this guide won't cover the linear running section in the trenches outside of the bunker that only occurs in a first playthrough.
Clipping out of bounds[]
Once the wake-up sequence is complete you'll be in a dimly lit room with bunker beds. Grab a nearby prop such as the medkit box and bring it to the wall by the bunker bed ahead of yours (it's the one near the lamp). When grabbing the prop it's important to pick it up a certain way. Keep in mind how prop clips work. Furthermore, it is advised to push into the wall at a diagonal angle. Henri will begin to bop up and down, and this is your tell that you're in position. After this, there's no need to use any movement keys to clip, it all relies on the regrab glitch at this point.
Moving around the staircase[]
You'll drop one floor down and land on some extended flooring out of bounds. Follow the floor around the staircase which leads up to the safe room. The extended flooring reaches just far enough so that it's possible to walk along the edge, but it's favourable to simply sprint and jump around the staircase to get past it. (In comparison to the extended flooring in Transept in The Dark Descent, this is plenty of floor to walk on).
Making it to the sub-level load trigger[]
Once you've passed the tight space around the staircase turn right and continue running along the extended flooring. You'll quickly notice the generator and the shaft down to the tunnel. Simply run towards the shaft to fall onto an invisible floor and initiate the loading sequence for the map below. While it is possible to fall off the map at this point, it should not happen as long as you had a clean angle towards the shaft. Inspecting the collision with debug mode is advised while practicing this segment in between speedrun attempts.
The tunnel[]
Once the load is complete, turn around and start manoeuvring along the ceiling of the tunnel. Again, it is advised to inspect the collision with debug mode whilst practicing this segment of the run.
Clipping back in bounds[]
After running along the ceiling for just a few seconds you will see a big boulder. Find the space between it and a collapsing frame where it looks like you will be able to fit through. Crouch and move slightly towards the left wall to drop down back in bounds.
The horizontal boost[]
Follow the path until you get to the top of a staircase. This is your opportunity to attempt a horizontal boost to save a handful of seconds in this next section. It is advised to jump later than one might think, in order to make it far enough forward to be able to hit the slanted wall at the right time. Jump once you've hit the wall and turn the camera towards where you want to go. Jump continuously to reduce friction, keeping the boost going for as long as possible. It is possible to achieve a boost so great that it ends exactly at the middle platform.
The shovel[]
Very conveniently there is a spade located at the centre of the map. Use this prop to prop fly to the end of the map, flying past the last staircase puzzle. It is advised to grab the prop only slightly above its middle point as it is a bit wobbly. Jump once to initiate the fly, then aim slightly upwards to barely tilt the prop towards you. This will ensure slight height grain throughout the prop fly. One should be very cautious about scrolling the prop towards Henri, as it is likely it will become too unstable.
The end[]
Once you've made it past the set of staircases all that's left is to run and crouch through the small opening and push away some rocks to complete the game.