Further details on Halo 4 have come out of Microsoft ExpertZone, a website used to teach retailers about the company's products. Little English Halo Blog has saved us all the trouble of digging for the information ourselves, so here are the highlights.
The game will feature ten new weapons, two additional vehicles "plus many of your favorites from the past," and multiplayer with "improved support to create, organize, and track groups." More interestingly, the site lists the first season of Spartan Ops as having five missions per week across a ten-week period.
That's 50 total missions playable alone or cooperatively, or "up to 12 hours of incremental gameplay" according to ExpertZone. Not bad for free content!