Halo (well, Bungie) revolutionized the console FPS. Halo had dual analog control (I'm sure there were FPS that had it before Halo, but I don't know what it is).

Halo (well, Bungie) revolutionized the console FPS. Halo had dual analog control (I'm sure there were FPS that had it before Halo, but I don't know what it is). Halo 2 introduced online play with playlists rather than servers (I believe they were the first). Those are innovations that sparked hundreds (thousands?) of copy cats. Not saying Wolfenstein/Doom didn't have a ton of innovations as well, but I think it's safe to say Halo took things to a completely new level.