Battlefield Heroes is a class based shooter. Like all class-based shooters, it offers a selection of different controllable players. Each class offers different advantages and disadvantages. Battlefield Heroes differs from most other class-based shooters in that there is a strong RPG element as class choice is permanent. Rather than players being able to select a new class on respawn or on game end, the player continues to gain experience with their class or "hero" and unlock access to new abilities and weapons.
Choosing your class
Class selection begins with Hero Creation, during which you first choose the Faction you want your hero to fight for followed by the Class you want to select. Once chosen, the hero becomes locked onto your account. Initially you may only make 3 heroes per account, but you may make more through purchasing additional hero slots.
The classes compliment each other when playing as a team and are often punishing to the players when many of one type are used on the same team. The classes match-up against each other in different ways with different loadouts, and as such, there is deep strategy in one on one matchups.
The Frontline Offensive/Anti-Tank class. He can use machine guns with large amounts of ammo and has a shield that will buff him and nearby teammates from enemy bullets for up to 60 points of additional health. Gunners are the only class that can use Tank Busters, which are medium/long-ranged rocket launchers that excel against Tanks and Jeeps.
The Support/Medic class that can heal teammates, throw Grenades and use Sub-Machine Guns. Some of their more useful abilities include Burning Bullets, hard-hitting incendiary rounds which set the target on fire, and Blasting Strike, a strange power akin to an explosion which sends nearby infantry and vehicles flying.
The Sniper/Ambush class that can snipe enemies from a long distances aided by the Piercing Shot ability. In addition to this the commando can use Stealth (invisibility) and Knives in surprise attacks from behind to great success. Some Commandos prefer Pistols over Knives or Sniper Rifles. He can also mark enemies, making them easier to kill.
In total you can level up six different game characters. Three Classes for each of the two Factions.
At this point in time (october 2013), It's quite improbable that a new class will be introduced to the game, since it has been stated by the developers in several threads on the official forum that they're currently not working and not planning the introduction of more classes into the game, and that the main balance is tweaking and re-balancing the 3 main ones.