Glitch

From TF2 Wiki

A Glitch is a bug or error in the game or map, but one which does not rise to the level of an exploit. A glitch would be something like not being able to load a menu screen or jumping out of the map by accident. By contrast, exploits are abusable to the benefit of a player using them.

Accessing Developer Console Unlike the PC version, the console versions of TF2 are not allowed to access the developer console. Occasionally, the host of the game can accidentally access this console. The way to access it is unknown but some have brought it up simply by doing an ÜberCharge. If the host has an Xbox 360 Chat Pad, they will be able to enter in text in the text box. (Occurs on Xbox 360)

Civilian Heavy (Patched) Whereby a Heavy is able to hold a T-like position similar to the hidden civilian class by revving his minigun (secondary fire) then switching his class to Heavy while in spawn. By switching his weapon to the shotgun or fists, he will appear in a T-like position, however crouching, standing still or holding the minigun will make the Heavy appear to be normal. The Heavy may attack while in this form, and moves speed-wise as if he is revving the minigun. If the Heavy revs or shoots his minigun anytime after preforming the glitch, he will lose the T-position.

Screenshot: http://gcnfire92.lenzus.com/content/35382115/r/l_76805732.jpg

Crab walking is an in-game animation exploit that can make the Spy move around in an amusing fashion that resembles a crab[1]. It is triggered by crouching while at the same time looking up with your disguise kit equipped. Often used by players who can perform it to humourous effect, it does not seem to affect gameplay directly.

Invisible 2Fort Bridge Roof Sometimes, a player will be able to see through the bridge roof on 2Fort. The shots cannot go through this invisible roof though. The cause is unknown. (Occurs on Xbox 360)
Inconsistency bugs
- Glitched Textures Sometimes after "alt-tabbing" or a server crash/disconnect, you can experience weird textures in some maps, namely spawn gates and water. It will look wireframe, usually in 2fort.
- Invisible Models Occasional occurs on the PC version if Alt-Tab is used whilst in full screen mode. Weapons fire can be seen but no player or weapons models. This usually only happens on one random player with the rest of the players still being visible and can lead to the player seeing the glitch to think the invisible player is using hacks. (PC only)
- On the PC, these bugs can sometimes be fixed by starting to record a demo and then stopping the recording process.
Invisible Weapons Occasionally a player will appear as if he doesn't have a weapon in his hands. The weapon fire is still seen and he's still in the posture as if he's holding one, but it appears as if he's not holding one. The cause is still unknown (Occurs in the Xbox 360 version and occasionally in PC and PS3 Version).

Losing the Aiming Crosshairs Occasionally, if a player leaves a laggy game and join a new game they can lose their crosshairs or aiming reticle. This reticle will not appear on screen however, the shots will go to where the reticle would have been if it were there. (Occurs on Xbox 360 and PS3 Version)

Losing Main Menu Sound Effects Occasionally, if a player leaves a laggy game or gets lagged out, they will not have any sound effects in the main menu. (Occurs on Xbox 360 and PS3 Version)

Mouth not Opening Sometimes when a player does a taunt or response, the characters' mouth will not open but the sound can still be heard. The Soldier will never open his mouth when doing a Shovel Taunt. (Occurs on the Xbox 360 Version and PS3 Version)

Over Player Limit If the room has too many spectators, the game will see that the room is still in need of players to fill it up. So, it will still be considered an open room. More players will be able to join and thus, the game will be over the maximum player limit. When the room goes back to the lobby and then they play another match, the game will automatically boot the players who recently joined who made it over the limit. (occurs on the Xbox 360 version)

Still on fire Sometimes after dying by fire you respawn and the burning effect remains around the edges of your screen, you take no damage and the disorientating sound is not present.

Opposite Team skins If a player who was playing as a Spy changes class, he will sometimes have the opposite skin (red or blue) of the team he is on. When you look at this player, the game will think that he is still a spy, and will display the "Disguised as enemy/friendly class" under his name, depending on the last disguise used. The actual cause of this glitch is unknown.

Sentry gun pistol fire When firing a weapon (commonly happens with the Pistol) at the same time as a Sentry gun fires its rockets, the gun's fire appears as it is shooting sentry fire.

Taunt While Dead If you happen to die immediately before you start a taunt dialouge line, your character will still say the taunt and even lip-sync while you are dead. (Happens frequently when taunting with the Bat)

Lag Glitches

Glitches caused by lag.

Flamethrower range Occurs all the time. Sometimes you can be instantly killed even when swept by the extreme range of the flamethrower, or the flamethrower has simply more range (not a critical swept).

"Netquake" Occurs rarely, but sometimes all players in the server will be unable to move and the player's view will shake (like an earthquake).

"Killed through a wall" Being killed by someone (with a direct weapon like a sniper rifle), despite being out of its view (and sometimes out of range). This is an artifact of Lag Compensation and is not an unforseen bug but an intentional design tradeoff in the networking code.

Sliding characters Some characters will assume default position (standing still) and slide instead of running around. The Civilian always assumes this position, and is not a lag glitch.