What's most impressive is how all three manage to navigate that tricky divide between crafting environments purely for videogame action and making those same environments feel organic and real. Station perhaps feels most artificial in this respect, purely because the arrangement of the trains feels too convenient, the corridors too twisty turny for any real public transport hub. Both Knee Deep and Nightfire excel, however. They feel like real places, and each element that adds to your tactical options seems to grow naturally from the place itself. Cellars, attics, balconies - none feel incongruous or out of context, but all quickly prove incredibly useful in your battles.
There's another element to this map pack, of course, and it's even more interesting than the multiplayer maps. Zombie Verrückt is an all-new scenario for Nazi Zombies mode, and it builds on the formula established by Nacht Der Untoten in very satisfying ways.
Based on the Berlin asylum that you battled through in the Red Army storyline of the single-player campaign, it once again pits you and three friends (or strangers) against relentless waves of the fascist undead. The map is oblong in shape, with an open courtyard in the centre. As before, each kill earns you points - as do revives and fixing the barricaded windows - and these points can be traded for new weapons or to remove debris to open up new areas.
New to the game are Perk-A-Cola vending machines (which can boost attack power, as well as reload and revive speeds) and an electrically charged barrier to fry the shambling horde. Both require power, however, and it's here that a little dash of genius is added to the mix. The generator is at the top of the building, on the opposite side of the map to your starting point. Getting there requires lots of points, and plenty of teamwork. That's because you're no longer all thrown together into the fray. Players are instead paired off, and separated from the other duo by a locked door which - you guessed it - needs power to open. Reuniting with the other players, and therefore raising your chance of survival, suddenly becomes as much about planning and tactics as repeated headshots.
It takes Nazi Zombies from a cute additional distraction to something approaching a standalone game in its own right - not quite on a par with Left 4 Dead, but certainly comparable in intent if not execution. The downside is that if you only have three players, somebody is going to be fending for themselves, and the odds of a solo player getting all the way to the generator are slim at best.
It's the addition of this new feature-set for the bonus game that ultimately makes this map pack a more compelling purchase, developing it from just another selection of new maps, great though they may be, into something more varied, robust and rewarding. We've come to expect map packs with our shooters, after all, but in the evolving Nazi Zombies experience the series now has its secret DLC weapon - and perhaps the seeds of a new spin-off.
Call of Duty: World at War's excitingly named Map Pack 1 is out now, and you can check out a trailer on Eurogamer TV.