Halo as a multilayer competitive FPS was never that great to me, but as a co-op PVE game it could be amazing. Halo's solo campaigns were awesome and epic, and the last games' Spartan Ops was pretty cool. I think Bungie found their true calling with Destiny. I remember playing Halo 3's campaign on co-op and having an absolute blast with friends. I hope they keep similar physics as far as gravity and movement goes.