You forgot about: l4d2 flamethrower l4d2 chainsaw l4d2 boomer l4d zoey and hl2 alyx making out

Also, good article. On the one hand I feel I wrung l4d out of most of its enjoyment factor (I got bored very quickly with it) and I feel I got all i wanted from it, but on the other hand there's that feeling of 'maybe this game was meant to be more and it just needs a little tender developer love'. Who knows.