Steam Weekend Deals for L4D2 (75% off) & Rock of Ages (75% off). In addition there’s Free Weekends going on for both. Play both games all you want until Sunday.
Can’t go wrong with either to be honest. I’m a fan of both games. Both deals end on October 29, 2012.
Since the L4D1 stuff was ported over L4D2, you probably could just buy L4D2. Only reason some people prefer L4D1 is because of the characters and play style is slightly different. If you pick up L4D2 definitely pick up the Helms Deep Reborn map and the I Hate Mountains campaign.
Rock of Ages Weekend Deal
Rock of Ages = $2.49 / £1.74 / €1.99
Most people know about L4D2 but Rock of Ages is pretty awesome. Basically, you have a big rock that you control and try to smash over things and eventually destroy your enemies gate. Once the gate is gone, you squish your enemy. At the same time they’re also trying to squish your guy, but you can set up various obstacles to get in their way. They recently patched the game and added a new multiplayer feature. Give it a try.