Quote from portal2tenacious on July 16, 2012, 10:22 pm

As an experienced speed runner, I have broken many maps.? There are those that play maps with the express purpose of finding alternate solutions and play testing.? I thought it may be wise to create a guide on how to not let speedrunners or casual players break your levels.? It will teach hardcore glitches, and how to prevent them.

Exfu glitch- this glitch is used by speed runners to "fly" through levels.? It is like noclip, but the player has a complete collision model.? If the player shoots a portal at a funnel, and shoots it at another wall, they can walk into it, crouch and uncrouch until they reach 0 speed (easily shown with they console command cl_showpos) and exit the funnel.? If still mooring crouch upon exit, they will float until releasing crouch or replacing/moving a portal.? If standing, they can exit the portal and jump from the ground whilst floating.? They will stay like this until a portal is replaced.? If the funnel is activated directly on a wall at the player's level, it is possible to do the glitch, but the only way to undo it would be to turn off the funnel, or, if crouching, uncrouch.? One thing that should be noted, is that the player must walk into he funnel, and may not jump into the funnel.

Reportal glitch- the reportal glitch is the product of the instantaneous portal placement, and the more enforced push. It is possible in the first portal, but the timing is very difficult. There were three ways to initially do it. One has been half-patched, as it can still be done on an angled surface. This method gains approximately 128 units of height with each reportal. Method 1- old ground reportal This method was patched with the dlc_1 update. It used to be putting 2 portals on the ground and firing while in the middle of the two. This can only be done on an angled surface. Method 2- wall reportal This method is used for gaining momentum when leaving 2 walls. If you fire a portal just as you come out, you will be pushed an extra distance. This can also be used on the ground, but the changing perspective can make it more difficult, and have less of a n effect then a ground reportal. Method 3- ground reportal This is the most difficult of the three reportals in my opinion. You put 2 portals on the floor, walk into one, and just as you're about to leave the portal, you shoot a wall. It also works as a peek-a-portal, and can be done anywhere, as long as the entrance portal is on the ground. It can be done for any amount time, but for continuous height, the player must replace the portal back to the ground.

Bunnyhopping- Bunnyhopping is a form of movement done by speedrunners to gain movement faster.? It is done by moving only the strafe keys in an alternating fashion, while moving the mouse back and forth.? This will make the player move noticeably faster than usual.? Paired with speed wallstrafing, this can be used to jump over 256 units.? The speed wallstrafe is strafing into a wall and moving forward to gain speed, then jumping repeatedly while looking about 10-15 degrees from the wall and only strafing inward to gain massive amounts of speed.? Bunnyhopping also can be done one sided by strafing back to the original position before another jump for a (as Sicklebrick calls it) "a fuckton of speed". Bunnyhopping is also paired with a circle jump, which is used to get speed quickly. It is a crescent moon motion-like skill that is very hard to master. It is most important for leaving elevators, because the elevator has a very important sequence for making it out quickly. It is a circle jump from the elevator all the way to the catwalk, wallstrafe,( not speed wallstrafe. No jumping) and jump at the right time to maintain speed through the door, assuming it opens soon enough, in which case you do another circle jump. This is used in every single portal 2 speedrun.

Propulsion gel crouch glitch- very simple glitch. Crouch on propulsion gel, move forward a bit and uncrouch, and you'll be at the top speed instantly. Very helpful for small patches of gel.

Peek-a-portal- I already mentioned this in reportal 3, but I think it should be it's own separate glitch. Put a portal on the ground, put the other portal somewhere, fall into the portal and shoot the same portal as the perspective changes. There are about 3 frames where this is possible, so it has become much harder in portal 2 than the first. This will also give a speed boost, as it doubles as a reportal as well.

Weird go through crap glitch- I don't know the real name, but this would only be good in a segmented speedrun of repulsion intro. I don't know too much about it, but if there is a thin floor, and you put both portals on a wall, go inside, crouch, save and reload, and you'll go through the floor. If done anywhere else, you will be trapped in the floor and will be capable of seeing no draw textures, assuming a map has it. Portals will remain placed after this.

Portal bump- I CANNOT BELIEVE I MISSED THIS ONE! portal bumping has been around since portal 1. It is extremely simple. Portals will move to the side, should the other portal be blocking it's way. It will even bump through or around a wall of 32 units or less. The only place this can be used is the slower routewall on turret sabotage.

Turret boosting- used only in the fast route of turret sabotage. Take two defective turrets, hold one, put the other on the ground. Push them together while on top of them and they will move each other upwards. This is very buggy and only works occasionally. You can see the effect by simply pushing the turrets across the ground.

Portal standing- very simple. Stand just out side a portal, shoot the opposite color, move back in. The push is not quite strong enough, but if VALVe gives more push, it's a better reportal for us.

Object hovering- igorsson did this in his route videos all the time. Simply jump on a cube, jump again, grab the cube, save, reload jump grab, repeat. This will let you jump up forever, assuming you're on a wall.

Button Save Glitch- this has been patched with the dlc1 update. It can still be done in older versions of the game. The player must step onto a button, step off and auto save just as they get off the button, reload. If the save happened at the correct time, the button will forever stay pressed. There is a version that works in the updated version, where all tis is dome with a cube instead of the player itself.

Object climbing- this is used to get up to places usually unreachable with portals. It requires two objects, usually a camera and a box. Place a camera on a box, jump on the camera, grab the box and spaz jump for extra height. The game keeps the box moving the camera that you jump off of. This is used for 2 portals on pull the rug.

Moon jump- This is done when a model or prop is squished a lot, messing up the collision model. It is moving around trying to be unstuck, and will let the player jump on it, send him flying in the air. This is used for 2 portals on pull the rug.

if I missed any, let me know so I can write an article on it.