Top similar games like Sirius:

Survival on Kepler is a race against time. Make the most of the remaining 168 hours or get turned into an unworldly being by the Sphere. Complete quests to help NPCs, explore the diverse landscape, survive wildlife and other players. Uncover Kepler’s mysteries and your mission’s true goal.

At the sunset of human life on planet Earth, you are a military pilot controlling a space ship, and you find yourself at the very epicenter of the battle in the solar system. You are forced to retreat into the unknown, distant Arcanum system through hyper-jumping.

In the distant future, the X universe faces a period of profound and irrevocable change. While the universe stumbles towards an uncertain future, countless adventures await as new enemies rise in search of power.

Infinity: Battlescape is a multiplayer space combat sim supporting hundreds of players on a single server. Join one of the corporate factions and fight for domination of a seamless, true-to-scale procedural star system. Participate in massive space and planetary battles involving hundreds of ships.

Azulgar: Star Commanders is a Sci-Fi open world sandbox game that puts you in a command of your own custom made space ship. Explore aftermath of the Azulgar event that reshaped the face of the solar system.

The ultimate space capital ship combat compendium is the evolution of hard core space combat sims. The only game of its kind currently in existence.

After a century in cryosleep you find yourself stranded amidst the ruins of mankind’s first interstellar colony. Explore derelict ships and stations and harvest raw resources in search of air, fuel and other equipment. Or loot and pillage what you need from other survivors. The choice is yours!

Physics-based VR with full freedom of flight. VR that feels and controls like a real jetpack. A real-time multiplayer VR arena.

Become the Captain of an interstellar cruiser and journey across the galaxy to save the Republic. During your journey you will have to make important decisions, improve the weaponry of your ship and fight against numerous enemies.

Build, Explore, Fight. Build a ship of your imagination, explore the vast cosmos, and fight for your stake in the galaxy.

Explore space and build on other worlds in Star Rangers! Star Rangers is a space exploration and construction game that allows players to build habitats and spacecraft, acquire gear and explore the solar system.

A single-developer passion project. A seamless full scale solar system. Thrilling action. Be part of an incredible journey as a Universe is built from the ground up!

Manage a space station, flying through a procedually generated universe, fight, build and survive in the coldness of space.

The ultimate space sandbox. Participate in epic fleet battles, form alliances, strive to dominate entire galaxies and harness the universe’s resources for your industrious empire or the destruction of others. Customise your experience, the universe is yours!

Red Planet: Survive is a first person survival game for Microsoft Windows. Surviving in the harsh conditions of the Red Planet will be hard, but if you are strong enough, you will succeed. Find the best way to survive, but be careful, since each wrong step will ensure your demise. The environment is your main enemy.

Create the Starship of your dreams, explore the vast expanse of the galaxy, land on planets and jump into epic space battles. Experience a truly unique and powerful building engine where your imagination is the limit. Welcome to the next evolution in Space Sandbox gaming!

The Moon has gone dark, cutting off Earth’s last source of energy. As a lone astronaut, you’ll explore abandoned lunar bases, solve intricate puzzles, and navigate stunning zero-gravity environments. Operate advanced vehicles, uncover hidden truths, and survive in this gripping sci-fi thriller.

Subdivision Infinity is an immersive and pulse pounding sci-fi space shooter featuring stunning graphics and tight spaceship game play. Hunt down and destroy enemy spacecraft, crush capital ships, mine asteroids for rare minerals, and find blueprints to craft amazing new vessels!

Take control of your own starship in a cutthroat galaxy. Elite Dangerous is the definitive massively multiplayer space epic.

Kinetic Void is a 3D space adventure with a focus on customization and enjoyable space simulation. The shipyard allows players to construct their ship piece by piece. Ships can be as simplistic as a cockpit, a hull, a engine and a gun, or as complex as a player wants.

Explore asteroid fields, trade rare resources, and upgrade your ship in Cosmic Miners. Navigate faction alliances, complete missions, and rise through the ranks in a dynamic space adventure where your choices shape your path to cosmic power.

Landinar: Into the Void is a top-down space-adventure-RPG. You are recruited as a rookie bounty hunter in the oppressive Landinar Empire. On your journey through the quadrant you will meet diverse characters, build your own spaceship and choose your battles.

StreamTeam is an upcoming squad-based strategic multiplayer game where you take part in an “away-team" fighting your enemies in space. Learn teamwork to defend your base from attackers, or leave your opponents in rubble. Get creative and become the best squad this side of the galaxy!

Space Travellers is a unique open-world sandbox space simulator set in the year 2343. Travel the galaxy, trade, explore unexplored worlds, fight, build bases and factories, forge alliances and experience new adventures!

Rebel Galaxy is a swashbuckling space adventure, with action-packed combat, exploration, discovery, trade, and “negotiation” with the outlandish denizens at the edge of the known universe.

Traditional survival in classic performance! This game is crammed with the joys, dangers and surprises of the genre. Your main task is to survive in a dangerous world. Put on the mask of a good-natured or villain, creator or destroyer, to get your place. Survive alone or in the company of friends;)

Mine asteroids, salvage space debris, design your own small or massive spacecraft using individual functional components, complete missions, and engage in battles against enemies in a vast galaxy with realistic physics based on orbital mechanics or in a classic physics mode.

Embark on an awe-inspiring journey through the cosmos with "The Universe of Red Hope," a mesmerizing space simulation game that brings the wonders of the universe right to your screen. 🌌✨

Elusive Verge is a third-person space exploration game with dash of base-building, combat and survival.

Space Battle VR is an action shooter set in space. It supports VR controllers to give you a real feel how it is to be a spaceship pilot. You can truly feel the cosmos with this game. Jump into an awesome adventure, help mankind, win a war, bring freedom and happiness to the universe. People need you!

The hit mobile game Interstellar Pilot 2 has come to Steam. Join the TEF forces heading to the Gatopean sector to find a new home for mankind. Play how you like in this open world space-sim developed by Pixelfactor.

Sci-Fi Builder is a sandbox sim where you command aliens, robots, and questionable space furniture to build your dream colony. No rules, no grids, no gravity problems—just you, 1188 ways to go wild, and a space station that desperately needs your weird ideas.

It is the year 2938. The long wished-for encounter of the X Universe and the Earth holds both joy and sorrow for the people. Despite flourishing trade, the clash of the diverse races, cultures and life forms creates new tensions, mistrust and open conflict that need to be overcome!

Endless Sky is a 2D space trading and combat game inspired by the classic Escape Velocity series. Work your way up from a relatively wimpy shuttle, cargo ship, or fighter, to a highly upgraded and customized flagship or to a massive fleet of warships or freighters.