The fantasy that Heat Signature caters to is powerful. You're a space mercenary, infiltrating large procedurally generated ships with your stealthy pod and taking down enemies from a top-down perspective, Hotline Miami style. It pulls this off thanks to an impressive cohesiveness in the world. You won't find a single loading screen or fast travel point in Heat Signature. It's up to you to get where you're going and take what you want.
What makes Heat Signature shine is a combination of items, precise controls, and time manipulation in combat. You can pause at any point, consulting your inventory and items (in other words, your choices). When an enemy spots you, time slows down, signaling that you have to act. You can tell how much tuning has gone into making everything perfect. The momentum of your character when you run, for instance. If you're careful, you can dodge bullets in flight. If you barge into a room of enemies, you'll have limited movement for the split second it will matter. The combination of slowed time and paused time gives Heat Signature an intriguing versatility. It can be both frenetic and contemplative at once. At one moment, you're desperately dodging bullets, and the next, you're calculating an involved step by step plan while paused.
The items you can bring with you and how they combine into different loadouts can make your mind boggle. Thirteen hours into Heat Signature, I still feel like I'm only scratching the surface of what I can do. Try to execute a "visitor" teleport into a room full of enemies, drop a grenade, then get pulled back to your original position in another room just before the bullets fly. The moment that grenade goes off is nothing short of exquisite.
If you do the tutorial, the game starts with you shooting out of a spaceship with only your suit keeping you alive. Lucky for you, you can activate the remote-controlled pod ship with only the press of a button. Your control switches over to your pod, which you guide to your hurtling body.
Heat Signature doesn't waste too much time on its premise. It's the Wild West in space, and you start as a mercenary on a small space station in a galaxy filled with small space stations. You pick one mercenary out of several options, each with their own "personal mission." These are usually along the lines of either saving or avenging a family member. They often have special perks or weaknesses, such as enhanced skills with melee weapons or bad aim. The choice doesn't really matter since you can switch between these characters whenever you like.
Sadie Fiasco, an old veteran residing at the bar of the space station, says she can help you accomplish your personal mission, but for a cost. To gather enough money, you have to do missions. At this point, the game stops providing any semblance of direction on what you should do, other than by progressively unlocking new mission types and items.
I found this to be both a blessing and a curse. I enjoyed the freedom, but the personal missions are bland and I don't see what the end goal of the game is. Since Heat Signature nails the fantasy and fun of what you're doing from moment to moment so well, it's a shame that it largely skips the setting and overarching purpose. I would go crazy for a Heat Signature with worldbuilding, lore, and a cast of interesting characters.
Attached to each mission are tags. These strongly hint to what kind of loadout you need to bring. For example, on some missions, you must avoid detection. On others you can't kill anyone, meaning you should bring non-lethal weapons with you. The mission board will also tell you what kind of tools the guards will have, such as shields or teleporters.
Missions always involve the same steps. Choose a mission, fly to the location indicated (always another spaceship), dock with your ship, accomplish the mission, then get back to base alive. The routine of getting to and from the enemy ship is relaxing and fun in its own way, and taking myself from place to place still hasn't gotten tedious thanks to the responsive controls and easy to use camera.
Mission objectives can feel a bit repetitive. Whether you're assassinating, saving, or capturing a target, it doesn't feel like this changes how you approach missions a lot. They mostly only change the final act (such as using a fatal or non-fatal weapon). The exceptions are the missions where you must take the helm of the ship, set a course to collide with an enemy space station, and then get out before it's too late. Often, this leaves you with just a few seconds to get out alive.
The main progression in Heat Signature comes in the form of liberating outposts. Once done, this lets you choose between a host of unlocks, such as new items in the shops. Since the gap in difficulty between missions and the personal mission is quite large, the game can feel somewhat grindy. The lack of narrative goals also adds to this feeling of a progression treadmill. If you die - which you almost certainly will at some point - you'll lose all your gear and money, and pick a new mercenary. All unlocked stations will still be available, including the items that you can acquire. While I feel like the existence of permadeath is essential to keeping the tension and risk/reward, there is an option to turn it off.
One shouldn't go into Heat Signature expecting handcrafted story and characters. It's more about the stories you make yourself, with the close calls, last stands, and ridiculous deaths. The game's mechanics and skill-based combat are a pure joy to play around with, and the seamless transition between different locations keep it from being a purely arcade-like experience. Unfortunately, the lack of any sort of end goal made me feel like I was on a treadmill grind earlier than I otherwise would have.
TechRaptor covered Heat Signature on PC via Steam with a code purchased by the reviewer.