Slime Rancher is the poop-farming sim you didn't know you needed

I love a game that is both as sweet as apple pie and as dark as pitch, and Monomi Park's bubbly sci-fi farming sim Slime Rancher is very much one of those. A sort of first-person Harvest Moon knock-off with a splash of Dragon Quest, it casts you as Beatrix LeBeau, a pioneer seeking her fortune on a distant planet overrun by squealing, bouncing, emoji-faced slimes. Feed a slime something and it'll squeeze out a "plort" (a frightful piece of onomatopoeia that puts me in mind of, ugh, "squanching" from Rick & Morty). Scoop up and fire that plort into your farm's market terminal using your trusty vacuum gun, and you'll earn cash. That's right, this is a game about the economics of poop, and the in-game Slimeopedia is only too happy to go into detail about what each creature's excretions are used for back on dear old Earth.

Of the relatively docile, omnivorous Pink Slime, for example, we learn that its crap is a key ingredient in coffee sweetener, cleaning spray and burger-mix - it's essentially the extra-terrestrial equivalent of corn syrup. The more hazardous Crystal Slime, meanwhile, supplies the manure for a variety of transparent construction materials, while the nocturnal Phosphor Slime's faeces are ground up to fill lightbulbs. A vision slowly builds as you bustle about the game's restful, warmly lit wilderness, planting crops and doing your best to keep your charges from eating the chickens behind your back - a vision of an Earth that runs entirely on slime products, an Earth walled and floored with shit.

If Slime Rancher is quite the agribusiness satire, those who like their games gutted of political relevance will be relieved to hear that it's also a charming, playful sandbox game. The core of it is straightforward - you alternate between roaming the planet's canyons (which are dotted with treasure chests, hidden grottos and sealed doors) in search of new slimes, and expanding your farm with new pens, carrot patches, poultry coops, fruit trees and the like, all constructed on preset building plots. Next to the sheer quantity of furnishings and cosmetic touches you'd find in, say, Stardew Valley, Slime Rancher may sound a little bare-bones, but it's lifted by the slimes themselves, who are (a) impossibly cute, even when they're squirting from the barrel of your vacuum gun, and (b) dangerously unruly.

Left to range at will, a slime will invariably home in on the nearest edible object, though you can distract them with toys such as beachballs. This includes plorts produced by other species of slime. If a slime eats another slime's plort, it'll become a Largo slime - a giant hybrid with the characteristics and dietary preferences of both species. This is good inasmuch as Largo slimes produce double the poop, and in two flavours to boot - breeding them is a great way to economise on space, though you'll probably need to beef up your containment facilities to cope. But if a Largo eats the plort of any other slime species, it'll morph into a Tarr slime, a oily monstrosity that'll consume anything and everything, duplicating itself relentlessly, unless you either spray it with water or hoover it up and fire it over the horizon.

The first time this happened to me it was because I'd accidentally fired a plort into a Phosphor Slime pen while serving up their daily repast of cubefruit (broad dietary inclinations like vegetarianism aside, each Slime breed also has a favourite food, consumption of which equals extra plorts). Within seconds, every Slime in the Pen had become a Tarr. That would have been disaster enough, but then the Tarrs broke through the energy net at the top of the pen and proceeded to eat my entire farm. Tarr outbreaks occur frequently while you're exploring the wilds - if there are more than two types of Slime in view it's wise to keep moving, though the fallout is usually entertaining to behold. You'll also have to worry about Slimes who have gone feral - these are usually confined to areas marked by skull-and-crossbone signs - and Slimes that are friendly but hazardous to be around. Consider the self-explanatory Boom Slime, with its expression of perpetual surprise.

Slime Rancher is currently free on Xbox One with a Gold sub (the reason you're reading a quick impressions write-up based on 10 hours with the game, rather than a full review, is that I wanted to get some thoughts out before the giveaway ends next month), and has attracted a small but enthusiastic community. The measure of a sandbox game will always be the number of ways players find to bend or break the rules, and there are some intriguing experiments underway - stabs at free-range farming, for instance, where players use things like toys and scarecrows to keep the roaming hordes in check rather than forcefields. I doubt it'll supplant Stardew Valley and co (though it's possible that, with updates, this could be every bit as gargantuan a timesink) but anybody looking for a squelchier, gently subversive take on the same concepts should definitely pick up a copy.