for uncharted i was thinking that they fight inside the plane like in the game and when the plane crashes they land in another characters level. Also i believe that Omar said in an e3 interview that the dreamscape stage isnt always the same, its only always turning into Buzz! for the demo.
That's good! I want to see a lot more for that level than just Buzz. To be honest, I don't see the big deal about Buzz..
Maybe there could be the monster from Rampage in the Sly level as the crossover.
Also, perhaps a Rapture stage for Big Daddy that includes Crash Bandicoot's Submarine from Wrath of Cortex smashing into the glass and flooding it.
But I would really rather Crash have his own stage.
well i never played killzone so i have no idea what those are. i just thought of another idea for drake's level. see you coul start out on the cargo plane. then in the middle of the battle the cargo plane falls in the desert just like unchrated 3. at the crash site you can have motorstorm vechiles driving by for the mash up thing. the can come at anytime and players could get run over.