I just got done playing a level of Left 4 Dead 2 on my MacBook Pro when I saw this: Valve has released the original Left 4 Dead for Mac OS X. Valve originally released the sequel, Left 4 Dead 2, for the Mac on October 5th, promising the first one would come in time for Halloween. The reason for the delay? Valve was having a bit of a hard time making the original Mac-compatible. Late last night, Valve made good on their promise.
If you're a fan of zombies, the original Left 4 Dead is a blast. It's also a steal at just US$9.99 (a 50 percent discount in celebration of its release), but for an even better value, you can get both Left 4 Dead and Left 4 Dead 2 for just $14.99 for a limited time. If you already bought the game through Steam on a Windows PC, you should be able to play it on a Mac now without having to re-purchase it thanks to Steam Play.
Left 4 Dead requires Mac OS X 10.6.4 or higher (Snow Leopard Graphics Update required) with a 2 GHz dual core Intel processor or better. You'll also need either an ATI Radeon 2400 video card or better or an NVIDIA 8600M or better.