15 Impossible Xbox Live Gaming Achievements Nobody Unlocked

3. What Are You Trying To Prove? - Left 4 Dead

Award for the most appropriately-named achievement yet, L4D's most egregious offender comes in the form of a difficulty-based challenge - getting through all the campaigns on expert. With the game's general pace already being absolutely furious and the amount of things that could go wrong in any given playthrough being numerous - people dropping out of matches, getting set upon by Boomers, running out of ammo etc. - having the additional health and item restrictions is a recipe for the most off-putting of experiences. Still, Left 4 Dead didn't become the household name it is today by not challenging zombie-killers and first-person shooter-lovers alike to learn the game inside out and apply that to one hell of a difficulty curve, but boy was this one that separates the hardcore from the casuals.