Team Fortress 2’s nine classes are divided into three areas: offense, defense, and support. Each team — BLU (Builders League United) and RED (Reliable Excavation and Demolition) — should ideally achieve balance between the three, although some of the game’s six modes (more on that below) may require more emphasis on one than the other two. As you complete achievements while playing a particular class, you unlock alternate weapons and headwear, as well as other unique items.

“My advice to beginners would be to try out various classes and find one that fits the way you like to play,” Walker says. “You’ll do better if your natural style of play fits the strengths of your class. Personally, I move around a fair bit, class-wise, so that I can understand what players are talking about when they’re discussing a particular class’s design.

“Right now, I’ve been playing a fair bit of sword-and-shield-using Demoman, which plays quite differently than the normal sticky-bomb-launcher-using Demoman. I’m not terribly successful at it, but I sure do enjoy collecting the heads of people on my Steam friends list.”

Offense:

• Scout: This rail-thin Southie (a native of south Boston) was the youngest of eight boys, so he not only learned how to fight at a young age, he also honed his hit-and-run skills. His scattergun is deadly in close quarters, while his pistol lets him pick off opponents from afar. Double-jumping gives him access to various nooks and crannies. His baseball bat comes in handy when he wants to think fondly of his favorite sport, or cave in a few skulls.
• Soldier: Rejection from the US military didn’t stop this Midwesterner from heading off to Europe anyway, where he hunted Nazis and awarded himself custom medals until he learned that the war was over. In 1949. The Soldier’s rocket launcher lets him unleash shock and awe on opponents and pull off those aforementioned rocket jumps. His secondary weapon is a shotgun.
• Pyro: Who is he (or she)? No one knows because the gas mask muffles everything he (or she) says. The Pyro’s short-range flamethrower not only sets enemies ablaze but can also blast compressed air that knocks opponents back, redirects projectiles, and extinguishes flames on teammates. A shotgun and a fire axe offer effective secondary attacks.

Defense:

• Demoman: This Scotsman’s bad temper is matched only by his prowess with explosives. His primary weapon is a grenade launcher, and his secondary one, the sticky bomb launcher, lets him spread around up to eight sticky bombs and detonate them when enemies get close.
• Heavy: He may be big and slow, but this Russian isn’t stupid, and his minigun can quickly make short work of multiple opponents. His shotgun gives him an effective short-range attack, and his unlockables include the Sandvich, a bologna sandwich that restores health.
• Engineer: This amiable Texan carries a shotgun and a pistol, but his main weapon is his PDA, which he uses to construct sentry guns, teleporters, and health and ammo dispensers. He can’t build more than one of each at a time, but his demolish tool lets him destroy the current construction and start over.

Support:

• Medic: Keep the dentist from “Little Shop of Horrors” in mind when contemplating this German doctor, who wields his syringe gun with deadly precision and uses his medigun to heal teammates and give them an ÜberCharge that makes them invincible for eight seconds. After collecting enough achievements, the Medic can unlock the Kritzkreig gun, whose ÜberCharge lets other players dish out nothing but critical hits for the next eight seconds.
• Sniper: G’day, mate. This Aussie’s primary attack is obvious; he also carries a submachine gun that he can whip out when enemies figure out his hiding spot and come running. His unlockables include Jarate, a jar of urine that causes opponents to take more damage from non-critical hits for a period of time. Jarate is also useful for putting out a Pyro’s flames and counteracting Spies’ cloaking devices.
• Spy: This dapper Frenchman’s most important assets are his disguise kit, which lets him appear as an enemy or fellow player, and his invisibility watch, which cloaks him for nine seconds. His knife may seem puny, but it delivers an instant kill if he is within 180 degrees behind his target, and his electro sapper lets him disable the Engineer’s creations. Unlockables include longer cloaking periods and the ability to fake his death.

BLU and RED are holding corporations founded by Blutarch and Redmond Mann, the dimwitted sons of wealthy Englishman Zepheniah Mann. Between the two of them, BLU and RED control all the world’s governments. The enigmatic woman known as the Administrator is the CEO of both companies; her reasons for pitting BLU and RED against each other in mortal combat are unknown.

The Administrator also serves the role of announcer during Team Fortress 2 matches, commenting on the action with emotions that range between mild anger and slight disappointment. “We knew we wanted an off-screen character who could talk to all the players in the game,” Walker says. “We liked the idea of the testosterone-heavy player characters being ordered around by a powerful female in an almost matronly and disapproving tone.”

He notes: “Over time, we found that play testers responded well to her reprimands, so she started to become more derisive. There are definitely elements of German World War II propaganda in her, as well as a dash of James Bond’s iconic boss, M.”

As you play its various maps, you’ll pick up other hints of Team Fortress 2’s over-the-top story world, such as the names of other companies owned by TF Industries, BLU and RED’s parent corporation. Zepheniah Mann’s ghost roams the Harvest map, freezing with fear for several seconds any player who gets too close.

Thirty-five maps are spread across the game’s six modes:

• Capture the Flag: Team Fortress 2’s take on this well-known mode involves grabbing the other team’s intelligence briefcase and bringing it back to your side’s headquarters. While the flag typically returns to its home when the carrier is killed, in this version, the briefcase remains where it was dropped for 60 seconds. During that time, the opposing team can grab it again, while the team that owns it can’t take it back. However, a player that is invulnerable can’t pick up the briefcase, nor can the carrier receive an invulnerability bonus.
• Control Point: In the standard variant, each team starts with the same number of areas under their control and a central point unoccupied. The team that captures all the map’s control points wins. In the attack/defend variant, one team owns all the control points at the beginning of the match and must keep the other side from grabbing them.
• Territorial Control: Both teams fight for control of territories. When one side is down to its final territory, the action switches to attack/defend control point gameplay.
• Payload: One team pushes a cart of explosives through a series of checkpoints, hoping to detonate it in the other team’s home base. In the Payload Race variant, both teams have carts, simultaneously putting them on offense and defense.
• Arena: This is a classic team deathmatch with a twist: a round ends when a team has no players left, or when the central control point has been captured.
• King of the Hill: These maps feature a central control point that unlocks after a certain period of time. One team must capture and hold it for three minutes to win.