All five game multiplayer modes have been detailed by EA's official blog for Battlefield 3. All of these modes—Team Deathmatch, Squad Deathmatch, Rush, Squad Rush, and Conquest—will be available for the nine multiplayer maps.
The classic Team Deathmatch mode will feature two teams of 12 players attempting to kill a set number of members on the opposing team. Since this mode has no vehicles, it serves as the perfect slaughterhouse for noobs welcome mat for beginners to get their quick fix and learn the ropes of Battlefield 3's multiplayer. As a variation, Squad Deathmatch pins four squads of four soldiers against each other with essentially the same rules, except for the inclusion of an Infantry Fighting Vehicle (IFV) which must be kept intact by Engineers.
The familiar Rush mode from Battlefield: Bad Company makes a comeback with a few adjustments, allowing 24 players on consoles but 32 players on PC. The attacking team must still attempt to arm and detonate pairs of M-COM stations with a limited supply of spawn tickets, versus the defending team's infinite supply of spawn tickets. Rush maps will include transport vehicles, armored vehicles, helicopters, and jets. To keep things fair, though, players can only take out an M-COM by arming and disarming a charge, not just be shooting it from afar.
Almost in opposition to the pair of Deathmatch modes, Squad Rush takes away vehicles and asks two squads of four to fight each other in close quarters on a map that only has 2 M-COM stations. Thus, this mode is the quintessential test for squad cohesion, customization, and communication.
Conquest is the grand-daddy of the five game modes, with the capacity to support 24 players on console or 32-64 players on PC. A variation on Domination rules, two teams must take control of various flags near each base to bleed tickets on the enemy team. If you're looking for large-scale, al-out vehicle warfare, this is the mode for you.
Finally, players can turn off vehicles switching on the "Infantry Only" option and can make the game more lethal and deliberate by turning a match "Hardcore". Not only does Hardcore remove HUD elements, but it makes matches more immersive, authentic, and tactical. Watch your back, or you'll get flanked right out of the game.