Breaking into ships, one airlock at a time
Heat Signature is a top-down infiltration game where you fly your pod up to a spaceship, dock with its airlock, and sneak inside. From there you pick your approach: creep up on the crew, take them down in slow-motion gunfights, or use gadgets to distract and outthink them. Missions ask you to steal loot, assassinate VIPs, or rescue people, and each one is randomly generated from a mix of guard kit, ship layout, and complications like space battles. You choose your own difficulty, from trivially easy to nightmarishly hard, and there's a practice mode where you can try items and tactics with instant restarts and no consequences.
The game leans hard on planning over reflexes. You can pause at any time, switch gadgets, aim, and fire with no time pressure, so you can work out a clever solution to an impossible situation instead of relying on twitch skills. Gadgets like teleporters, stealth shields, and subverters let you invent your own answers, and ships can be torn apart with breach grenades or fuel barrels, including getting sucked into space through a breach. Zooming goes smoothly from a view of the whole galaxy down to your character sneaking up on guards inside the ship you're boarding.
Playing with friends
Heat Signature is not multiplayer. You are never in the same world as anyone else, and the friends features are about sharing content rather than playing together. If a friend's character gets captured and they can't rescue it, you might get a character whose personal goal is that rescue, and pulling it off unlocks their character for you to play. Retiring an accomplished character lets you pass on one named item, which your Steam friends and your future characters have a chance to find as loot, and you'll pick up items your friends have named too.
Remote Play Together is listed as a Steam feature, so one person can host and others can join in from their own machines.
What to know before starting
Deaths are permanent in the sense that each life is a new character: when you die, you pick someone new with different starting kit and continue in the same galaxy. Every character also has one grand heist to work toward, like rescuing their brother or getting revenge. Completing missions moves you toward liberating space stations from the empires, which unlocks gadgets to buy and special challenge characters.
The game is not story-driven in the usual sense. There's a backstory and some conversations, but no plot that develops as you play — the stories come from how you got out of a bad spot. You also can't mine asteroids, build ships, or recruit a crew; you're an infiltrator and that's the whole job. The setting is a nebula full of space stations, with no planets and no space exploration.