Outside of the limp finale, the only things worth complaining about in The Sacrifice relate to how little you're getting compared to The Passing. Like The Passing, it's only three maps long, but this time only two of those maps are new. Remember the small last map of The Passing, with the original Left 4 Dead survivors hanging out by the bridge? That's the last map of The Sacrifice.
And while The Passing gave us new weapons and items, a new special infected and new survival and scavenge maps, The Sacrifice gives us... explosive barrels. In its defence, they're pretty interesting explosive barrels, because they set the area around them on fire for a while, making them as dangerous as they are useful. But still. Explosive barrels. Left 4 Dead 2 owners also get a port of No Mercy and some new mutations, but that's it.
It wouldn't quite be true to say that The Sacrifice makes up for all of this with the two new maps in its campaign, but they are excellent, even if they do make a return to the more bleak industrial environments of Left 4 Dead 1. We were spoiled by Dark Carnival and Swamp Fever, I suspect.
The first map, The Docks, has a great Crescendo Event early on where you need progress through a sealed train car containing a Tank (and the bodies of a whole load of people that got locked inside with it), giving your team the chance to set up a trap before setting the maddened thing loose. Later on, Valve showcases its talent by turning a boring-sounding train yard into an astonishingly ominous and dramatic backdrop.
From here you move on to The Barge, which is my new favourite map in any Left 4 Dead campaign because of its centrepiece - an enormous, six-storey pile of grit, with the walkway to the barge resting on its peak. Aside from being a striking image, it creates some really bizarre angles for the zombies' attacks.
They can either run up one of the sides of the pile, meaning you're less likely to see them until they're on top of you, or they can go sprinting from the barge up that long, hopelessly narrow walkway, which provides you with a hugely satisfying fish-in-a-barrel chance to gun down dozens of them in a few seconds. But it's all over too quickly, and then it's on to that disappointing ending with the map you've seen before.
I do wish it was as simple as congratulating Valve for putting out more fun, free DLC, but it's not. The Passing was a relatively easy purchase on the 360; if you're still playing Left 4 Dead 2, it's worth the money. But this is, inarguably, significantly less content for the same price. Only dedicated deadheads need apply.
6 / 10
Left 4 Dead 2: The Sacrifice is available to download for PC and Xbox 360 from today.