“Left 4 Dead” (rated M, $30 for PC, $50 for Xbox 360): This week’s free downloadable content means that all four of the game’s campaigns are now playable in versus mode. More importantly, the download makes available a new gameplay mode, “Survival,” in which players fight off wave after wave of undead, with each wave getting more intense than the last. A couple of friends of mine and I tried out Survival Mode shortly after it became available and loved it. A word of caution: Try to round out your team with four real-life people. Computer-controlled characters’ instincts to heal wounded players tend to kick in at the most inopportune times. Maybe the next tweak Valve could introduce to the game is a feature that lets players “switch off” computer players’ use of first-aid kits on others unless the human players specifically request it, via some sort of button press. It’s also worth noting that Survival Mode apparently has a glitch that stops special undead from spawning after about 15 minutes or so. It’s also worth noting that only the most skilled, dedicated, coordinated foursomes have a prayer of lasting that long.

“ExciteBots: Trick Racing” (rated E, $40 on Wii, $50 for game
and Wii Wheel): This trick-oriented racing game features vehicles in
the shapes of insects and other wacky creations. It’s the latest in a
series of games that includes the original NES “Excitebike” as well as
Wii launch title “Excite Truck.”

“Fallout Trilogy” (rated M, $20 for PC): Don’t let the “trilogy” in the title fool you. This bundle doesn’t include “Fallout 3.” Instead, you get “Fallout,” “Fallout 2” and “Fallout Tactics: Brotherhood of Steel,” all highly rated games from Interplay. If you’ve played “Fallout 3” and loved it, this newly released bundle is a great way to catch up on what you’ve missed. It’s worth noting, though, that these three games play nothing like the blend of first-person shooter and role-playing game you’ll find in “Fallout 3.” The first two games are top down role-playing games with turn-based combat, while “Fallout Tactics” is a squad-based, tactical RPG. Despite these gameplay differences, if you fell in love with the world of “Fallout 3,” you’ll find plenty to like here.

“Rock Band 2” (rated T, prices vary based on configuration): If you don’t plunk down the $2 for REO Speedwagon’s “Take it on the Run,” released this week, your ’80s cred merit badge oughtta be revoked. The song is being released as part of an REO Speedwagon/Styx tour-related package. It’s worth noting, though, that the Styx tracks are recent rerecordings sans Dennis DeYoung. And “Come Sail Away” and “Mr. Roboto” aren’t among them. Now that we’ve got “Take it on the Run,” maybe “Sister Christian” will be next. Other relatively recent standout tracks include The Shins’ “New Slang” and Glasvegas’ “Geraldine,” below.

“The Orange Box” (rated M, $10 download for PC, this weekend only): If you don’t already have “The Orange Box,” which includes “Half-Life 2,” “Half-Life 2: Episode One,” “Half-Life 2: Episode Two,” “Portal” and “Team Fortress 2,” this is a no-brainer. Any one of these five games is worth $10 by itself.

What I’ll be playing this weekend: It seems like I write this every week, but I’ll be working on some more “Killzone 2.” It’s a fine game, but it really hasn’t grabbed me by the throat and pulled me in yet. Hopefully this is the weekend. I’ll also be going back to “Fable II” and perhaps “Fallout 3.”