Yup, you see the base explode of the ship get of of the tanker a movie plays and you see how you changed the world etc, then you get a chance to play on.
Many new things are opened up, I havn't ever gotten this far yet so I don't know what but there are plenty of things
Well actually not too many things open up. Actually its quite disappointing. The only real thing to do is kill every living thing on the map....i mean everything. Other than that just start again!!!