This game is great when it comes to multiplayer, zombies, co-op campaign and modding.

Great zombie, Co-op, FPS. It comes with all the L4D1 maps and a lot of tanks.

Great tower defense for those who want something with zombies. Although, not as great as the version with the Michael Jackson zombie.

Great FPS and "Co-op" game. More challenging than Nazi Zombies. Anyone have any dosh?

Great if you want a challenge two steps up from the binding of isaac. Have fun dieing!

Even though they through it onto the orange box, it still redefined the source engine. Psst, the cake tastes great.

Great second part to the story line. Can't wait for the third installment *cough*. Recommend playing original before this, but who's stopping you ;)

The original that took the gaming community by storm. Recommend playing this first before Half-Life 2, but who's stopping you ;)

Gives you a three fold expansion onto the original game and wrath of lamb. Recommend to play original before playin rebirth (see TBoI recommendation)

Great rogue-like that is challenging, but also makes fun of pop culture. Recommend to play base game, then get wrath of lamb (buggy, but enjoyalbe).