The lights are on
I just conquered the latest Portal campaign with a random stranger on Steam, and it was glorious. This free DLC pack is easily on par with what other publishers would charge $10 or more for.
The just-released "Peer Review" DLC has two components: a two-and-a-half hour long (or so) cooperative campaign accessed through a new passage in the co-op hub, and a challenge mode with matching leaderboards for both single-player and co-op. Both are up to Valve's usual sky-high quality standards, even if competing for speed runs is something I don't see much appeal for in Portal 2.
The new co-op campaign, however, is brilliant. It skillfully combines all of the wonderful puzzle elements that made Portal 2 amazing to begin with into new configurations that will bend your mind even if you've played Portal and the sequel to death. As always, the excellent HUD indicators partners can bring up for each other make working together easy, even if you're stuck with text chat instead of voice like my partner and I were today.
I was glad to see the return of the underused white gel for one long segment, and the addition of buttons that turn off Material Emancipation Grids required some new tricks to make it through GLaDOS' latest diabolical challenges. A few spots demand more in terms of twitch skill and timing than Portal 2's single-player campaign, but the manual dexterity requirements aren't as steep as in the original co-op levels either.
GLaDOS herself is hilariously sociopathic as always. Valve did a nice job of keeping her from being entirely one-dimensional, though, as you get to hear a tinge (and perhaps more than a tinge) of fear in her voice on occasion. The story throws a fantastic curveball in at one point that turned my constant chuckles into outright belly laughs. The ending on its own is an incredible distillation of what makes Portal's universe so compelling for us all.
The challenge mode offers leaderboards and cool curves showing the global Portal 2 community's scores and your place among them for both time-to-completion and number of portals used to finish levels. It's a neat idea and all, but I just don't see myself spending much time rehearsing perfect runs through Portal 2's puzzles. The fun for me is in solving them, not executing their solutions.
I was amazed at Valve's ability to keep Portal fresh through a full-length sequel when Portal 2 came out, and I'm equally impressed by Peer Review. This remarkable DLC pack shuffles Portal 2's deck of tricks and deals a brand new hand of funny, challenging, mind-bending, thrilling content -- and all for free. I suggest you flag down a friend (or even a random stranger) and dive into Peer Review post-haste.