In his review of Gunpoint, the first game from former journo Tom Francis, Dan Whitehead described the protagonist as a "flea in a trenchcoat" - springing through windows to administer dainty mouse-click beatdowns. To continue the theme, Heat Signature reminds me of those horrible wasps that breed by paralysing tarantulas, laying an egg on them and leaving their larvae to burrow into the poor creature, gobbling it up from the inside out. In this case, the tarantula is one of an endless series of procedurally generated starships, made up of cunningly stitched-together sentry gun chambers, hallways, keycard doors, fuel cell rooms and treasure boxes. The wasp is an unarmed but perilously agile single-seater pod, able to swoop across a twinkling 2D starfield and snap itself cleanly over an airlock in a matter of seconds.
And the larva? That would be your character, a scruffy vigilante out to stop an interstellar war by killing or abducting each faction's captains, stealing technology, hijacking vessels, rescuing captives and, once you've done enough of the foregoing, flipping space stations (which serve as mission select hubs and shops) to your cause. Your tools in this noble endeavour range from some beautifully bizarre teleport doodads and time control devices to that essential instrument of peace-keeping, the wrench. The sum of these parts is a wonderfully versatile, chaotic, lo-fi mixture of house-breaking sim and space roguelike, muddled a little by some uneven performance. If insect metaphors make your skin crawl, think of this as a bunch of Hotline Miami maps flying around a galaxy and you're halfway there.
You steer your pod by pointing and clicking, your character using WASD. The interface is rather busy, but pausing the game throws up a little window revealing every special keyboard command possible in the context.
Heat Signature is a game's worth of hectic anecdotes - precisely the kind of emergent storytelling bonanza you'd expect from a developer who once penned book-length accounts of feats of silliness and calculation in 4X strategy games like Galactic Civilisations II. As per fine Spelunking tradition, the best stories are often those in which you do something idiotic and must wrestle with the fallout. Here's a favourite: I've shot, stealthed and bludgeoned my way to the helm of a Sovereign battlecruiser, knocking the pilot the length of a corridor with my energy hammer, then downing my bounty with a concussion rifle when he moves to investigate. Having purged the ship of guards, all I have to do now is return with the body to my pod. Instead, I decide to be clever.
I slip behind the wheel of the enormous craft, pivoting magnificently to unleash a barrage of rockets at a passing ship. The other captain returns fire with rather more accuracy, slicing the nose off my conquered cruiser and plunging myself and my bounty into vacuum. As the oxygen flees our bodies, I take remote control of my pod, detach it hastily from the cruiser's airlock and fly it around to scoop us up with around 0.3 seconds of lung capacity to spare. It's a tale for the ages, matched only by that time I ran out of emergency fuel while flying a half-wrecked pod back to base, and was obliged to eject and propel myself the rest of the way using the recoil from my shotgun. Chew on that, Matt Damon.
Thanks to the game's generous contextual slow-mo, you can dodge bullets at reasonably short range - enemies aren't great at leading targets. Shotgun blasts are another matter.
Or how about those teleporters? Heat Signature does things with the concept of teleportation the likes of Corvo Attano could only dream of. My favourite model is the Visitor, which snatches you back to your origin point after a couple of seconds. Once upon a time, I found myself squaring off against a woman in a hallway with a shotgun wielding only a knife. Fortunately, I still had one charge left in my Visitor, and used it to warp two rooms across, narrowly escaping a cloud of buckshot. In the fleeting window before the return trip kicked in I opened a nearby loot crate and discovered, glory of glories, a grenade launcher. The guard, meanwhile, had run down the corridor past my original position, and was thus completely oblivious when I popped back into view, armed to the teeth, like some kind of self-inflating Rambo.
There's also the self-explanatory Swapper, which you might use to bypass a door you don't have a key for, or whisk an attacker straight into the path of his own bullet. This latter feat is especially satisfying if you're surrounded by enraged space samurai and the shooter happens to be wearing an explosive vest. It's less useful if the subsequent blast overheats a nearby fuel cell, ripping the hull open and plunging everybody into space. But don't despair - providing you survive the experience, you can plug your pod right into the gap rather than circling back to the airlock. Think of it less as a disastrous reversal, more a bonus shortcut.
Choice upon consequence upon choice upon consequence - Heat Signature is good at indulging the urge to overreach yourself, wring chaos from even the most humdrum scenario. But as with Spelunky and co, the game's sheer volatility would be nothing without its stable fixtures, its bendable but predictable checks and balances. The most straightforward is each airlock's location - always on more-or-less the opposite side of the ship to whatever it is you're after - and (usually) the need to avoid triggering the alarm, which will cause the enemy pilot to set course for the nearest allied space station. Allow the ship to reach that station - the exact travel time varies from around 20 seconds to over two minutes - and you'll be captured, forcing you to start over with a new character. You can, however, put a stop to this by slaughtering the pilot, which creates a quandary whenever the alarm is raised: do you beat a retreat to your pod, abandoning the mission, or mount a desperate assault on the bridge?
Your best friend either way is the space bar, which pauses time so you can change the items mapped to your mouse buttons, scroll around the layout and fine-tune an action plan in the event of, say, a bunch of dudes in body armour teleporting to your position while you're hacking a sentry gun. The game also slows time when you enter an unaware enemy's vision range, granting you a few, precious seconds to break line-of-sight before an alert is triggered.
In general, Heat Signature is happy to let you "cheat" for the sake of a more entertaining outcome - you can teleport any dropped item on the ship to your inventory in a pinch, for example, and there's no fog of war to hem you in. It has a very relaxed attitude to failure, too - a single hit is enough to K.O. your character, but guards always resort to tossing you out the airlock rather than polishing you off, allowing you to rescue yourself and replenish your gear at a friendly station before trying again. You can't shrug off damage indefinitely, because every injury you take equals a shorter countdown to expiration when thrown into space, but there's scope for two or three raids on each ship before the risk of character loss becomes significant. Characters are, in any case, easy to come by, recruited from the gaggle of Raymond Chandler-esque roughnecks - each with a random combination of items - slumped against each station's bar.
There's a backstory of sorts, involving a veteran ship-stealer, but it's pretty lightweight.
Beyond the basics, each mission adds its own peculiar mix of enemy loadouts, security systems and overarching variables. In one mission, you might pitch up against soldiers equipped with heat sensors and personal shields that activate when the alarm sounds. In another, you might have to worry about rescuing a captive while a second ship batters the first, blowing away compartments one by one. Certain clients will pay you more if you carry out the mission without being seen, or without harming anybody, or without leaving any crew members alive.
It's a ripe old stew of constraints and possibilities that grows all the riper as you conquer base after base, adding new makes of pod, new weapons and new gadgets to each station's marketplace. If you do begin to tire of grinding those bases, there are extra-hazardous Personal Missions for each character (pleasingly, these include rescuing previous characters from captivity), and Defector missions - custom-crafted puzzle scenarios that hand you a particular combination of items. You might, for example, have to rescue somebody from a ship with multiple keycard doors using nothing but a Swapper and a Glitch Trap, which teleports its victim a few dozen metres in any direction.
Heat Signature's only serious sore spot is its engine, which, on the plus side, allows you to zoom Sins-of-a-Solar-Empire-style from a majestic view of the cosmos to a close-up of your doughty adventurer stabbing somebody in the kidneys, but is also given to sporadic slowdown. This is especially apparent when you pull the camera back while touring larger vessels, though it perhaps owes something to my choice of PC, which has only the minimum 8GB RAM requirement. The art direction is also a touch sterile, a balance of flourish and function that skews a little too hard toward the latter. There are bright spots, though - each faction offers a distinct and colourful style of ship interior, and your pod has the grabbable dinkiness of a vintage toy car.
Heat Signature is, in theory, another empire-building game like Far Cry or Assassin's Creed, in which you prise away nodes of geographical control, amassing plunder if not XP or character levels. It never feels like that, though. It cultivates an air of supreme disposability instead, its ships thrown together only to be picked apart as you'd pull the legs off a spider, its adventurers little more than loadouts with funky labels and an optional bespoke final mission. Inevitably, this framework rings a bit hollow after a few hours of continuous play (you could spend upwards of 20, I think, reeling in every last space station and beating every last Defector quest) - these systems remain charming to the finish, but there's a sense that Heat Signature is reliant on players being heartily sick of games that invest such acts of open-ended vandalism with broader significance. Forgive it that, however, and this is a piratical delight.