In a world without sports announcements, 343 Industries revealed exclusive gameplay footage of Halo 5: Guardians. The gameplay revealed 4 player online co-op and showcased some of the pyrotechnics and heavily scripted action sequences that we've come to expect from gameplay reveals. The enemies showcased were the Prometheans from Halo 4 and the covenant (of course).
Additionally, they revealed a new war zone game mode, with massive maps and the infamous enemy AI as the enemies, as well as the usual red vs. blue dynamic. Apparently you also get to play as a hunter.