It’s the weirdest Fallout: New Vegas DLC yet. I went back to the Mojave to pit my brains against the worst that 1950s B-Movie science has to offer. Is Old World Blues an enjoyable trip?

Old World Blues is the only DLC I’ve ever played that ticked me off for rushing through it. I wasn’t even going to complain about the length. Purely focusing on the critical path, obeying orders and going from A to B like the good little questbitch you are, you’re not likely to be disappointed by either its length or content. But Old World Blues is deceptive. On the surface, it’s a tiny new chunk of the Mojave Wasteland to explore. In reality, it’s bursting with new stuff.

This is the kind of DLC I like to see – not just more of the same, but an interesting spin on Fallout: New Vegas that both fits the universe (unlike, for instance, Mothership Zeta back in original Fallout 3) and tries some new ideas. The main one? Cranking up the crazy technology we’re used to seeing to full on MAD SCIENCE! levels, to the point that having your brain replaced with a Tesla coil by a Think Tank of disembodied scientists locked in a war against an army of roboscorpions is barely the seventh or so weirdest thing that happens to you.

What really makes Old World Blues a joy though is its sense of humour. It knows how silly it is, and it utterly embraces it. Obsidian’s obviously been playing a lot of Portal recently, but it comes through in all the right ways – the crazy characters, the hilarious back-and-forths between the squabbling scientists, the snide messages on terminals, and even a few bits where you outright enter test chambers to solve problems and retrieve fancy guns. Unlike Portal though, you get full RPG interaction with everyone and everything, letting you fire a few shots back at the arrogant machines – literally or figuratively – and twist them around your little finger – figuratively. Hell, at one point, as long as you’re packing the right Traits, you can seduce a lightswitch.

Most of the good stuff relies on surprise, so I’m not going to ruin too much of it here. Essentially though, there are two main questlines in Old World Blues – the main one, in which you try to escape, and a second involving finding the AI components of your new flat, which will give you toys like a new AutoDoc capable of resetting your Traits (as a one-time thing), and a hydroponics machine that sounds like Barry White and demands your seed. This second one is presented as a scavenger hunt, although really the World/Local maps tell you exactly where to go, and it’s more a way of taking you to the locations you wouldn’t have found. It’s worth not simply running in, grabbing the disc and running out though, as the design throughout this expansion is excellent. Visually, it’s completely stock Fallout 3-style architecture for the most part – and by god, do I hope Fallout 4 never reminds me of these buildings – but the little vignettes and mini-stories in each of them are all excellent. As with the expansion as a whole, they’re often more detailed than they look, with options to redo tests at higher difficulty levels, or simply cheat. Sneak through a building without being detected by the droids? You can do that. Or you can just blow up the droids before starting the test and amble across in your own sweet time.

Old World Blues is intended for Level 15 characters and above, and playing through, that seems right. If you have anti-robot gear, you’re going to be at an advantage early on, but it’s far from essential. Once you start, you’re not allowed out until you finish it. Afterwards though, you get a teleporter that will bring you back and forth whenever you like – although not with any of your companions. It’s worth trying to wrap everything up in one go though, purely so that the characters involved get to have their say in the ending sequence – which as ever, offers multiple ways to resolve things, up to and including getting the dreaded finger-wag.

The only real downsides of the expansion are that it takes a while to get into, with an opening that can easily be half an hour or so of almost nothing but dialogue. However, it’s funny dialogue, and calms down once you start properly. Also, while there are more enemies to fight than lobotomised zombies and roboscorpions, you’ll soon have more than your fill of both. Beyond that, if you enjoyed New Vegas but weren’t inspired by the first two packs, this is definitely the one to jump back in for, not least to prepare for next month’s finale.