Alternatively, if you've yet to add them to your collection, The Orange Box will set you back £14.99/$19.99 USD on the Xbox Store, with Left 4 Dead and its sequel each coming in at the same price.

Want to play Left 4 Dead, but can't spare a megabyte? Left 4K Dead might be more your size. A simple, free web game inspired by Valve's co-op shooter, Left 4K Dead was developed by Markus Persson ...