The game:
Vex can be divided into 10 different segments: The Tutorial, Acts 1 through 8 and the Credits level
Before I talk about the run there are a few things I have to explain:
Corner clipping:
When you cancel a wallslide with the down arrow, your vertical speed gets set to 0 and your ceiling collision disables for as long as you are moving down, this is used to cut corners on the bottom of blocks way tighter then usually possible.
Water momentum glitch:
In the game, there is a variable that determines your speed while swimming, the game moves you with that much speed into the direction you are facing.
When holding the up arrow in water, the game first checks if your speed is below 5 and if so it adds 1 to your speed
When not holding the up arrow in water, the game first removes 0.4 from your speed and if your speed is below 0 it sets your speed to 0
(Holding the down arrow does not affect your speed and simply moves you back by a constant amount, so it's not relevant)
The maximum swimming speed appears to be 5, however, if you have between 4 and 5 speed and hold up your speed still increases by 1 since you have less than 5 speed and you will end up with a higher amount of speed than 5 afterwards you can continue swimming at this speed.
The most optimal up press pattern then becomes:
- 0.0 speed Not moving
- Forward - 1.0 speed (+1.0) Getting to 5 speed
- Forward - 2.0 speed (+1.0) Getting to 5 speed
- Forward - 3.0 speed (+1.0) Getting to 5 speed
- Forward - 4.0 speed (+1.0) Getting to 5 speed
- Forward - 5.0 speed (+1.0) Got to 5 speed :)
- Nothing - 4.6 speed (-0.4) Slowing down by 0.4
- Forward - 5.6 speed (+1.0) Increasing by 1, going over 5 speed
- Nothing - 5.2 speed (-0.4) Slowing down by 0.4
- Nothing - 4.8 speed (-0.4) Slowing down by 0.4 again to put the decimal to .8 which is the best possible value you can get
- Forward - 5.8 speed (+1.0) Speeding up again to get to the max speed possible
- Continue holding forward going at 5.8 speed
IS WHAT I WOULD SAY, but for whatever reason doing another 2 frame release after this gets you to 6.0 speed, something that was found after the previous TAS was made, and so all swimming sections are a bit faster now.
Fake Transition Glitch
When you exit out of a level, control over the player is taken away, your horizontal velocity is ignored (not your vertical velocity) and the transition into the level hub happens. While this transition is active, the player is unable to interact with any death hitboxes, which means you're invincible to most things. This isn't really useful normally because you can't really do anything with it, but if it wasn't useful I wouldn't talking about it.
For whatever reason, when you enter the menu for the stage builder and then go back to the main menu, a weird state will activate where any time you enter the options menu and then close it again, it will start a transition as if you were exiting a level but then the game will cancel it after it ends and you will just continue the level.
The reason this is useful is because this means you can be invincible at any moment you want, at the cost of not being able to move horizontally for 1 second. This is used 3 times in the run to save a massive amount of time.
Ok, now I'm finally ready to talk about the run!
The TAS:
Main Menu:
In the main menu I set up Fake Transition Glitch and then press the button that starts the game (starting the game is very important, otherwise it is not possible to complete).
The Tutorial:
In the Tutorial I jump very late into the first wall, because you can walljump while moving upwards, you can get over the wall very quickly.
After that are some walljumps, I made sure to walljump as low down as possible so I can get onto the block as early as possible and then skip the section with the purple blocks by simply walljumping off the ceiling block.
At the bouncer block I start a wallslide at the side of the bouncer since that very quickly reduces my vertical speed and allows me to activate it way earlier than just jumping on top of it, I also hold up as that places you a few pixels higher for some reason.
In the ending I use the mentioned corner clip to get past the final block at the end as fast as possible with some funny movement while falling to get the best possible position.
Act 1:
In Act 1 I begin by walljumping up the starting area to skip about half of the level
The other half of the level is skipped by doing a precise corner clip off the block above the ending portal, by using corner clipping you can make the jump all the way to the portal.
Act 2:
The beginning should be pretty self-explanatory
About 8 seconds into Act 2, you can stand on the very edge of the block with spikes on it, the hitbox doesn't actually fully cover the top of the block.
After waiting a short bit I walljump off the orange block and back to the main level to skip a tunnel section with shurikens in it.
I get a little boost from a conveniently moving green block and enter the water section where I swim to the end using the water momentum glitch.
Act 3:
In Act 3 I start by getting to the bouncer block, however, when bouncing on it I reset the level using R. When you reset a level (or respawn from a checkpoint) while on a bouncer, you will spawn at the height of the bouncer you were on and then get the bounce, so I can use this to skip a small part of the level.
After that is some sick shuriken dodging and the rest should be pretty easy to follow, just skipping some purple platforms.
Act 4:
Act 4 is the first time that Fake Transition Glitch is used. Here it is used to skip past the death plane that normally prevents you from skipping the level by dropping down from that section. Because you keep falling with this glitch I can just fall through the death plane like it isn't even there and save a couple of seconds.
Act 5:
Act 5 should be pretty easy to understand.
Act 6:
In Act 6, you can get a small push from the block with the spikes in the water with a precise position and angle, I would explain it if I knew why it happened. :P
It might look like I lost some time getting the key, but this is intentional:
There is a small region above the spikes where you can get inside of the spawning radius of the spinning sawblade thing at the end of the level. Going into this region saves a lot of time in the ending as you don't have to wait for the cycle.
The position of the player is also carefully manipulated while grabbing this key to allow for a very precise jump. Normally this jump is just barely out of reach, but by turning around you extend your hitbox a bit further forward which allows you to land on the ice without having to jump off the ledge first.
Act 7:
Yeah you can kinda stand on the edge of the beginning keyblock.
Hold on, how did we just clip through the other side of the wall??? When you cancel a wallslide, you get a large downwarp. If you are falling fast enough this downwarp can send you to below the point at which the ground tries to push you up, and so the wall collision activates. Because you're moving away from the middle of the block that you are clipping into, you get pushed to the side and so you can skip the entire level.
Act 8
In Act 8, I once again do Fake Transition Glitch, this time while running on a booster block. Because your horizontal movement is ignored, you are free to build up more and more speed on the booster. Boosters do not have a speed limit so you can build up a huge amount of speed. With enough speed, you go through the wall because collisions are ignored off-screen. Doing Fake Transition Glitch also re-centers the camera to the player, so it's used a second time to avoid flying into the abyss.
Credits
Soooooo about the water section... I COULD explain how the collision system in this game works and how all of these pushes and clips happen, but that would probably triple the amount of text in this TAS description and I don't think anyone would care enough to read all of it.
At the end of Credits, I do a smart little optimization with the keyblock. You see, you could just run back a little and then run right again to get the most amount of momentum before being able to get past the keyblock, but you can actually get in between the keyblock and the sawblade while it's opening to be just a little more to the right when the keyblock hitbox disappears. (This saves 1 frame so it is vital to explain this in detail).
And that's Vex beaten in 4 minutes and 3 seconds RTA time! Hopefully you enjoyed it and thanks for reading my explanation all the way through :)
