The Mortuary Assistant has me sweating embalming fluid, and I keep coming back

Step one of being a good Mortuary Assistant is pinning the mouth. There's a dull, soft thud as the nailgun-like device in my hand fires a metal rod into the corpse's gumline. Top and bottom jaw, of course; more thuds. It's followed by step two – sewing the mouth shut. The teeth are drawn stiffly together as I connect the new pins with metal wire and twist it taut. All the work stays behind those colourless lips, so when the molars are finally forced together and I pull my fingers out from the drying maw of the carcass, the mouth drops into a passable imitation of a peaceful smile. 

Step thr– what was that noise? I glance up from the body, peering about the dark mortuary with the upset agitation of somebody who's trying to convince themselves they're more embarrassed than scared. It's raining and after dark, with moonless rain drumming relentlessly on the window. For a moment, two of the droplets run down the pane next to each other, and catch the light of the surgeon's lamp above me, turning them into a rough facsimile of white, watching eyes looming in the black – but that's just my traitorous imagination at work.

I pick up the trocar – a device that looks like a foot-long iron syringe – and prepare to flush the corpse's abdomen of excess fluid. Down the hallway behind me, something giggles as though enjoying a private joke. When I look at the glass again, the droplets are gone – but the window is hanging open, a chill breeze running through the room.

Exorcising is good for you

Cards on the table: The Mortuary Assistant is pretty freakin' scary. Created solely by developer Brian Clarke, the game has a rather simple, albeit effective premise – you are a young Mortician named Rebecca who joins the obviously haunted River Fields mortuary, and is dropped in the embalming fluid when it turns out that demons are running rampant and hiding in the corpses. Somebody needs to do something about it, and fast, before the shadowy horrors try to make the jump into – say – the inviting body of a troubled morgue worker.

Rather than go full Doom Slayer or break out the Proton Packs, Rebecca's approach is a little more cerebral. Work out what demon is hiding in the bodies, which body it's dwelling in, and then perform an exorcism and cremation on the offending corpse. Oh, and the other dead folk still need to be prepared as normal, because you're nothing if not an unrelenting professional, even when hungry hellghouls are trying to sunder your soul. 

Take too long, exorcise the wrong body, or screw up the ritual by misidentifying the demon, and you'll be the next carcass laid out on the rattling gurney. And while this is going on, spooky – though largely harmless – little events happen all around you, serving as a constant reminder of your impending doom and providing details on Rebecca's rather bleak history.

Lurking nine-to-five

I admit to having my issues with The Mortuary Assistant, mainly on the mechanical side of things. The detective demon-deduction bit is a great idea in theory, but the clues often feel arbitrary. You're not so much following a complex train of logic and reasoning, as you are just waiting for the game to hand over information when it feels like it's ready. And considering the timer ticking implicitly away in the background, that's not a good feeling, as it's less than productive.

Speaking of which, I wish I had more idea of how long I had until succumbing to full demonisation. The game provides a pen and pad, assuring you that freestyle scribbling on it will reveal just how much of your spirit has been chewed up – but most times I tried, it just came out as gibberish and wonky shapes I had no idea how to interpret. Let's see, according to these post-it notes, I'm… half a backwards penguin closer to possession than I was twenty minutes ago. Hooray?

Sometimes dead is better

But you rarely notice faults in the thick of things, elbow-deep in a dead man's gizzards while looking nervously over your shoulder for approaching horrors you know damn well you don't actually want to see. The game's larger scares and backstory setpieces aren't too freaky, but when it goes subtle and quiet, The Mortuary Assistant can be heart-stoppingly nasty – a shifting shadow, a silhouette half-seen, a motion at the window that defies explanation… It's so much scarier when it takes its foot off the pedal and lets your imagination fill in the blanks, occasionally even reminiscent of Phasmophobia in its ruthlessness.

I also like the very blunt and uncompromising presentation of the embalming process. I have no idea how accurate it is to real life, but the ghoulish practice of preserving corpses and literally flushing the blood out of bodies helps keep the macabre nature of the game constant without being overly dramatic. When the best thing that can happen to you is the chance to rearrange a murder victim's anatomy unaccosted, you know you're in a very bad situation.

The Mortuary Assistant has its issues – it's pretty short, a little rough in design and graphics, and marred by the occasional glitch – but it nails the atmosphere and moment-to-moment experience so magnificently that I'm willing to forgive a lot from it. The electric jolt of seeing a shadow watching from down a hallway, or hearing a rustle of motion by my ear got me every time, and it's restrained enough with the scares for the tension to ratchet up palpably between them. Give The Mortuary Assistant a go if you're interested in puzzles, atmosphere, and the chance to organically ruin at least one pair of underpants.

Looking for something even scarier to play? Check out one of the best horror games that you can download today.