Team Fortress 2 (TF2) is an online multiplayer game released by Valve in 2007. The core gameplay has 2 teams both fighting for the same objective. Any player can play 9 different classes. The objectives each team tries to accomplish changes based on the game mode you play on. The most popular and well-known game mode being "capture the flag," where you try to grab the other team's intelligence.
There are 3 different types of classes. There are different customizations each class can have.
Offense characters consist of Scout, Soldier, and Pyro. These classes are the ones that would go ahead of everyone else to do the best they can on clearing out the area. When the opportunity strikes they will attempt to take the objective.
Defense characters consist of Demoman, Heavy, and Engineer. These would be used to keep back anyone who tries to advance. They will sometimes try and advance by themselves, which can be helpful, but will sometimes become a war between the defenses on each team.
Support characters consist of Medic, Sniper, and Spy. These classes will help other classes in different ways. None of the support characters conventionally support in the same way.
Scout is the first class. He wields a scattergun, a pistol, and a bat as his stock weapons.