Has a 64 players (32v32) multiplayer format with multiple gamemodes, some of which are smaller at 16v16. The favorites seem to be Campaign (map of Vietnam, where you choose factions and slight buffs/debuffs every time you change map, and alternating teams pick a region to attack, and Territories which is a single map with 5 points (Alpha thru Echo) with either North or South Vietnam forces defending or attacking.
Southern Forces (US Army, USMC, ARVN, and ANZACs) get helicopters and all the niceties of a 1960s-1970s western military. Northern Forces (Viet Cong, Vietnamese Military) get traps, and cobbled Soviet, Chinese, and old French military equipment to use in battle. They also use squad tunnels to spawn instead of being able to spawn at their Squad Leader's location like the Southern factions.
Squad Leaders for both sides can mark fire support locations using binoculars or Signal Smokes if you're a Southern faction. One player on each team is also the Commander, who can call in Artillery and Scouting runs, and uniquely for the Southern forces are Napalm strikes (US Army, USMC), Spooky gunship support (US Army, USMC) and Carpet bombing runs (ANZACs). Northern force commanders can set up off-map AA missile positions to defend against the gunships, bombing runs, and any player helicopters who fly too high while they're active.
Game is currently buggy as all hell, but its still fun imo. Worth checking out if you have the desire to.