Battlefield 3 fanart, showing the four classes.
Support: Carries a big gun and shoots at everything. Kinda like Animal Mother in Full Metal Jacket.
Assault: Both a Medic and an assault class. He can revive people that got shot in the head with a defibrillator.
Engineer: He solves practical problems.
Recon: Makes 12 years old scream about hacks, camping, mothers and playing a "weel class".