Clear the beer cans off your couch—the next chapter of the game that redefined the first-person shooter has finally arrived. Using the new Forge feature, you and up to seven combat cohorts can build custom levels in real time on Xbox Live. “All eight of you can design the level together, then press a button and immediately play it,” says Halo co-creator Frank O’Connor. “When you’re done tuning it, go share it with the entire community.” Hit the Saved Films function to get a God’s-eye view of the action—and see how MasterBeater19 just stomped your strategy. Then slap some Plasma Grenades on your belt, fire up your Brute Chopper, and hunt down that sneaky bastard like he stole your (neglected) girlfriend.