I am still not completely sold on this guy walking around as the main character...You are going to be looking at his back the whole time...I just think it is silly that he would just shoot up...It would be different if he would be able to do a 360 degree turn...the game is also going to be constantly moving, pushing the player foreword so even if the character is standing still the stage will still be moving...it sounds like a real bed Atari game.
The game engine is being built for a ship...but whatever.
Maybe in the story the guy has some sort neurological problem from the nuclear fallout that makes it impossible for him to turn his body :D
Also...3 frames for an explosion??? In a 60fps game...will the human eye even pick that up?
More thoughts later :)