Battles in Call of Duty: Modern Warfare's multiplayer offering vary quite a bit. You can get into fights with just one teammate at your side in the new 2-on-2 Gunfight mode, or you can take on an army of opponents in Ground War. We went hands-on with Ground War at Infinity Ward's Modern Warfare multiplayer event, where we took part in a few hectic 20-on-20 matches. Check out our gameplay in the video above.According to Infinity Ward, when Modern Warfare launches, Ground War will support more than 100 players. We saw a lot more at the Modern Warfare multiplayer reveal, including six-on-six matches featuring more tactical modes like the new Cyber Attack, and slightly larger fights such as Headquarters, which sported 10 players per team.Infinity Ward has made a big deal about how with Modern Warfare, it's trying to create a unified experience. That's in contrast to the previous Call of Duty games, which might have felt more like three separate experiences packaged together. Your progression unlocking guns, attachments, and equipment will all carry through from one mode to the next, which should make Modern Warfare's multiplayer, single-player campaign, and cooperative Spec Ops mode all feel like they're taking place in the same universe.