The second obstacle to bringing Player Two into the fold are the expectations they believe Player One holds. As the sage and poet Jim ‘txshurricane’ McLaughlin observed in earlier hallucination/article Let the Wookie Win, Player Two might laugh for a while over how bad they are at a game, but they will soon lose heart if they feel they are an impediment. Regardless of how encouraging or patient Player One is, their new ally is likely to acutely feel that they are slowing the game down, depreciating its value, sucking the fun out of the room. Whether this is actually true or not is beside the point, and the genius of the majority of gun games is that Player Two cannot negatively impact the performance of the team.
Compared to Resident Evil 5 or Gears of War where the death of one would be the end of the game, exacerbated by sections requiring the players to split up, lightgun games allow the victory to be shared but the loss to be isolated. In Extraction, Player Two may join, drop in or out, and have an experience that whilst they are alive they have a direct and deliciously crunchy effect on the necromorph threat. Should they die or use their ammunition unwisely then at worst they become silent until the next checkpoint or level, never feeling that their own inexperience has detracted from the game, building their skills with every pull of the trigger.
With these two key obstacles overcome the way is laid open to a world of more intense and more gloriously compulsive habits. Passing around that innocuous little white stick at a party feeds the need to master the controlling paraphernalia required to get the really good stuff. Any Player Two that kicked necromorph ass around the Ishimura is on the verge of mainlining Halo. At that point they’re a "Requiem for a Dream" montage away from calling Player One’s place of work and telling them he’s sick the day Reach came out. Pull down the shades, stock up on Cheetos, from then on its all just kiss kiss, bang bang.