If you're of the mindset that fart jokes are more puerile than they are top of the parps, stop reading now. Know that this game has little to offer you, and move on. But if you're more of a playground-humour persuasion, this platform-puzzler is occasionally a gas.
After one of your doofus janitor duo guzzles a bottle of an extremely fizzy drink, he develops quite the emissions problem and fills up his suit. Which isn't so great for his grumpy purple pal, given that the pair are tethered together by an air hose, and so can't stray far from one another. It is, however, more useful for you – tapping Y switches which of the twosome is inflated to a great girth, and shrinks the other back to normal size. And that one gag stretches to form the crux of Shiftlings' humour – two somewhat underdeveloped characters farting at one another to swap sizes.
Little and large each have their advantages. The former is nimble and sprightly, able to fit into compact spaces, pull switches and dart about; the latter is slow and ungainly, but can activate pressure pads, serve as a trampoline and – most fun of all – drag his companion about like an unwilling lhasa apso on a leash. Playing solo, you switch between them by pressing B or move them in tandem by holding LB; there's also the option for you and a friend to control one apiece in local or online co-op.
The puzzles take the form of platform levels, each with an endpoint to reach. But sometimes, you reach your goal and are then turned around and told to go back. It can feel a bit directionless, which isn't helped by the fact that some sections are geared around collectible cola bottles – and these aren't always clearly differentiated from your main objectives.
It's all, naturally, easier in co-op – two heads being better than one and all that – but requires tight communication to co-ordinate who needs to be where, when and at what size. Most of the fun, we found, came in making friends go all fat when they least expected it. Simple pleasures. Solo play is fiddlier and involves a sure grasp of timing, but co-op is by no means an essential.
The central size-switching mechanic may lose a little of its charm over time, and the game's lurid colours soon grate, but as in any puzzle game worth its space dust, the best moments come when something new clicks into place. When you realise you can use the big guy as a counterweight to pull the littl'un up and on to a ledge, say, or twig that moving platforms make great jump-off points from which to bounce on your outsized pal's head. It's neither as chaotic nor as amusing as it wants to be, but these space goons still sweep up some fun.