Glitches (Test Subject series)

A list of all currently known glitches and bugs in the Test Subject series. Due to all the games in the series sharing similar engines and mechanics, some glitches can be seen in multiple games. Many of the glitches in the series are caused by the behaviour of teleporters or the fact that a wide variety of characters with different mechanics can be played in the same environment.

Note: For the remainder of this page, "Rex209" may be used as a character name to refer to both Blue Rex209 and Professor Rex209 as both characters have almost-identical behaviour and mechanics in their games.

Frozen Startup screen
Games: Test Subject Blue, Test Subject Green

As of late June 2017, Test Subject Blue and Test Subject Green no longer advances past the startup, rendering the games completely inaccessible.

Portal clipping glitches
These glitches are caused by the way teleporters behave in the games and allow the player to use them in unintended ways, such as ending up in the wrong end of a portal upon traversing it. Portal Clipping glitches are often more difficult to perform than other glitches in the series and require a high precision with the character's movement.

Turnaround clipping
Games: All Characters: All

This glitch allows the player to clip through any vertical portal in the game by using precise walking movement. Unlike many glitches in the game series, turnaround clipping can be performed without a proper setup or knowledge of how the glitch works, by just walking up close to a portal and quickly imputing left and right movement. However, there are ways to make this glitch more consistent.

Whenever the player is standing still they can slightly press both directional arrow keys in quick succession, starting with the one opposite to the way they were facing, to do a short step backwards while keeping their character orientation. Doing that very close to a teleporter while facing away from it can result in the player moving a couple pixels at a time into it, which can eventually lead to the character clipping through without being teleported. The timing for this glitch is very precise, but relatively failsafe since the player only has to input short left and right movement keys over and over until they have successfully clipped. It is possible for this glitch to be easier to perform in certain games or situations, and with certain characters.

Portal bumping
Games: Test Subject Arena 2 Characters: All

This glitch allows the player to exit a portal the opposite way it was intended to be, and can only be performed with three-block high vertical portals. The player has to jump through a portal while walking in one direction and then change their direction while jumping, which will allow their character to collide with the block on top of the portal, which at a specific angle has a different hitbox from the normal solid blocks. Colliding with a solid block which a portal is connected to pushes the player away from the portal, which allows the player to clip through the portal the wrong way. This glitch is very precise, but if performed correctly, allows the character to end up on the other side of the second portal.

Because of the nature of this glitch, the movement inputs required to perform it differ for all characters, due to their different speeds. It is recommended to use a fast character like the Professor or Orange for this glitch due to their high mobility. Furthermore, the portal-clipping glitch has to be performed differently when using Blue in Rex209 or the Professor in Rex209, as they will try to land on the block on top of the portal, but will be unable to do so because it is connected to the portal.

This glitch can also be performed without the player having to change their direction while in mid-air. The player still has to time their jump very precisely in order to clip with the top of the portal at the right angle. Clipping through the portal this way allows the player to teleport to the other portal facing the wrong way, but still moving in the same direction, essentially making the player enter the second portal and exiting the first one they went into on the other side. Performing this glitch this way is more difficult than when changing directions while in mid-air because the player cannot monitor their angle of approach as much and has to rely on perfect timing, making this version of the glitch much more unreliable.

This glitch cannot work if the portal the player is trying to clip into is embedded in a wall, as the top block of the portal does not have the proper hitbox. The portal has to have a platform or ceiling on top of itself for the collision to properly work. This glitch also cannot be performed by entering the portal from the left. The player has to enter the portal from the right in order to clip into it at the right angle.

Animation buffering glitches
These glitch are all performed by inputting a specific action during a character's animation, which will prevent the action from happening but will still carry some of its effects if the button is held. This can lead to the character performing multiple actions at once, often resulting in unexpected animations.

Super jump
Games: Test Subject Blue, Test Subject Green and Test Subject Arena Characters: Blue and Green

When the player respawns to a checkpoint after being killed, they can hold the up and shoot buttons during their respawning animation, resulting in them rocketing up into the air as soon as they regain the control of their character. The character will be accelerating upwards at a fast rate, which can allow them to traverse the entire level vertically if they don't bump into a ceiling. The player can use the left and right movement keys to slightly adjust their trajectory.

Turnaround sliding
Games: All Characters: All

Whenever a character starts walking towards the opposite direction they were previously facing, a very short turnaround animation will be played. This animation can be paused into a single frame if the player holds both the left and right buttons during it. This means that if the player starts holding one direction and almost immediately starts holding the other direction at the same time, they will start walking while frozen in their turnaround animation. For example, if the player is facing left they can hold the right and then the left button a few frames afterwards, which will make them slide right until either direction is released or they press any other button.

Additional behaviour with Rex209
This glitch has different properties with Rex209 due to their unique ability to shoot while walking without slowing down, as well as to recoil back when standing still and shooting. Since they lack a turnaround animation, this glitch will result in them sliding "backwards" as they stay in their standing animation, facing the wrong way. Shooting while sliding will not break their slide, but instead will slow them down to a halt, where they will be frozen in place. Shooting once more will make them slide in the opposite direction (the one they appear to be facing). Any subsequent shot will make them accelerate, allowing them to travel much faster than their default walking speed. Furthermore, their bullets will be incorrectly fired to the side of their actual sprite, making them able to shoot through walls. If a turnaround slide is performed by Rex209 on a ceiling, they can pick up enough speed to outrun their bullets without getting hit by them. However, as soon as they go through a teleporter or they drop off their platform, they will be hit by their own shots. If they do not hit themselves, they can carry their acceleration into a ground slide until they hit a wall.

Idle walking
Games: All Characters: All except for Rex209

If the player starts holding the jump button while airborne and continues to hold it as the they land on a platform, the character's movement actions will be impaired as long as the jump button is held. The character is unable to crouch, and moving left or right will cause the walking animation to continue playing, even if the character stands idle. The walking animation can be canceled if the player shoots, and crouching only has effect on the player's momentum.

Flickering falling animation
Games: Test Subject Arena 2 Characters: All except for Rex209

If the character falls off of a platform without jumping, and the player holds the crouch and shoot buttons simultaneously, the character will act strangely. The character sprite will rapidly switch between frames of its falling and air-shooting animations on every frame until they reach the ground or the buttons are released. If the glitch is performed with Professor, he will have his normal falling animation but will repeatedly play his attack sound without attacking.

Shooting aerial jump
Games: Test Subject Arena 2 Characters: All except for Rex209

If the player falls off a platform without jumping, they can press the jump and shoot buttons at any time during their fall to perform a short jump in the air. Since the character ended up in the air without jumping, they can still use their jump if buffered during an attack, resulting in them doing a ground attack quickly followed by a short jump while not being on solid ground. It is possible to start holding the jump button as soon as the character drops from a platform and shoot at any point during the fall to perform the aerial jump.

Shooting aerial jumps are much shorter than usual jumps and only lift the player half a tile upwards, though if performed immediately after leaving a platform they can allow the player to jump up to two and a half tiles. Though these jumps are short, they can be useful by resetting aerial momentum. The height gained from a shooting aerial jump on the edge of a platform can vary from one character to another depending on their speed and firing speed.

Neither Blue in Rex209 or the Professor in Rex209 can perform these jumps, an will just shoot normally. The Professor can perform aerial jumps, but his melee animation will be canceled by his jump before having an active hitbox, resulting in him not attacking and only jumping.