This is very easy, as you can get it playing solo. Simply go to story mode, and then versus. You will get an achievement just for doing that, then select 2 player and pick your stage. You take turns doing each part of the stage, after 1 person completes it, it rewinds so 2nd player can go. You don't have to worry about kinect not picking up a 2nd person, the game just tells you to hand off the gun and shoot when ready. Score more points as player 1 and achievement unlocked.