Team Fortress 2 consists of nine different playable characters. There are the attack classes, Scout, Soldier, and Pyro. There are the defense classes, Heavy, Demoman, and Engineer. Then, there are the support classes, Medic, Sniper, and Spy. (Berghammer, "Team Fortress 2 Hands-On Preview") They take on a cartoon-ish style, "like a Pixar-animated movie." (GameSpot, "Half-Life 2: Episode Two - The Return of Team Fortress 2 and Other Surprises")
The Scout.
Image courtesy of Valve Corporation.
ATTACK CLASSES
The attack classes Scout, Soldier, and Pyro all have different gameplay mechanics.
By default, the Scout has a 'scattergun' shotgun, a pistol, and a bat. The shotgun holds six shots per clip and is best effective at close range. Unlike other classes' shotguns, this one fires and reloads much faster. The Scout is the fastest moving class, not counting any speed boosts. His speed allows him to get up close to the enemy and dodge their aim.
The Soldier is equipped with a rocket launcher, shotgun, and shovel. Aside from shooting enemies, he can use the rocket launcher to propel himself or enemies using the explosion's knockback. The Soldier is one of the slowest classes in the game, right behind the Heavy.
The Pyro uses a flamethrower, shotgun, and fire axe. His flamethrower can be used to ignite enemies, which will then take damage for a few seconds. It can also be used to blast enemies or projectiles, such as rockets, to the area where the player aims.
The Engineer.
Image courtesy of Valve Corporation.
DEFENSE CLASSES
The defense classes Heavy, Demoman, and Engineer all have different gameplay mechanics.
The Heavy's loadout consists of a minigun, shotgun, and his fists. Most often, you will see a Heavy equipped with a sandwich instead of a shotgun. This is useful for teams, as he can give it to teammates as a health pack. The Heavy's minigun comes with a fast rate of fire and high damage, but makes him slower. Heavy is already the slowest class in the game, but combined with firing, he becomes an easy target. He has 300 hp, compared to most classes 125-200 hp, to make up for his slow speed.
The Demoman wields a grenade launcher, a stickybomb launcher, and a bottle. He can use his grenade launcher to fire at enemies. The grenades will explode on contact with an enemy, or roll around on the floor for a few seconds until exploding. The stickybomb launcher can be used to set traps in doorways or choke points. He can set 8 at a time, though 4 will usually be an instant kill, so setting multiple is ideal. All 8 will be detonated at one time.
The Engineer is one of the most useful classes. He is equipped with a wrench, a shotgun, a pistol, and a PDA to create and destroy buildings. He can create four buildings, and can have only one at a time. He can make a sentry turret, which will automatically fire at enemies that come in its range. It can be upgraded using the wrench and scrap metal. At level 2, its fire rate increases, and at level 3, it can shoot rockets as well. He can also create a dispenser. It will heal teammates and replenish their ammo. It can be upgraded to increase the rate at which health and ammo is replenished. The last building he can create is a teleporter. He can create an entrance at the team's spawn, and an exit right near the front lines. It allows the team to quickly get back into the fight. It can be upgraded to increase the rate at which players can use the teleporter. (Goldstein, "Team Fortress 2: Class Warfare")
The Medic.
Image courtesy of Valve Corporation.
SUPPORT CLASSES
The attack classes Medic, Sniper, and Spy all have different gameplay mechanics.
The Medic is one of the most important classes to have on a team. He uses a medigun, which can heal teammates, as well as a syringe gun and a bonesaw, which can both be replaced by weapons that can also heal teammates. He doesn't have too many defenses, so it's the team's job to keep their medic safe. He also can use an Ubercharge on a teammate, making them invincible for a few seconds.
The Sniper can use his sniper rifle to pick off enemies from a long distance. If an enemy gets close to him, he can retaliate with his SMG or knife.
The Spy can use his invisibility to go behind enemy lines and get picks on unsuspecting players. He can backstab an enemy with his knife, always resulting in an instant kill. If he needs to, he can use his revolver to ward off enemies trying to attack him.
ctf_2fort, one of the over 100 different official maps in the game.
Image courtesy of Valve Corporation.