The only planet we've been able to check out is a section of Earth. It includes the Cosmodrome free roam area, Devil's Lair Strike mission, a small Story mission (and by small, I mean very small), and finally the Tower. As for multiplayer, coined with the name The Crucible, we've been able to play one gametype on two maps. The gametype is called Control which is basically Territories from Halo. The two maps reside on Earth and the Moon. Very cool stuff!