Officially, Bungie has added Double Team Training gametype, which is an unranked 2-on-2 match, and has now given gamers the option of playing Big Team Battle as a ranked match. Unofficially, a few custom matches have been unlocked showing off unrevealed features such as the Escort mission and automatic team switching. Fans of the original Halo will enjoy a glimpse of of the M6G pistol in use, a derivative of the first game's M6D without a scope.
We've embedded two videos of the custom games after the break. One video was purported to have been done via modding, whereas the other was reportedly done through perseverence. Said the video's narrator, "we kept trying [to get into a custom game] and it worked ... this is a real game, no modding involved."
[Via Xbox 360 Fanboy]