Single-player games like Space Simulation Toolkit
Below are 8 single-player Steam games similar to Space Simulation Toolkit, ranked by player overlap. Every pick carries Steam's Single-player category, so multiplayer-only titles or always-online games don't sneak in. imho.run pulls the category data from Steam directly — Single-player here matches what the store labels.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like Space Simulation Toolkit page.
Ranked picks
- 1
SpaceEngine
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Indie and Simulation with Space Simulation Toolkit.
The world's first science-based photorealistic interactive 3D planetarium that models the entire Universe, using procedural generation for uncharted areas.
- 2
Universe Sandbox
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Indie and Simulation with Space Simulation Toolkit.
Create & destroy on an unimaginable scale with a realistic physics-based space simulator. Explore the beauty of our universe and the fragility of our planet. Use science to bend the laws of gravity, collide planets, boil away oceans, fire epic space lasers, and customize your universe.
- 3
The Bibites: Digital Life
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Indie and Simulation with Space Simulation Toolkit.
Explore real digital life in The Bibites! Play god by guiding your bibites on their evolutionary journey or engineer your own. Analyze their Neural Network brains and genetic information as they adapt to their environments. Save your favorites and test their strength in Challenge Mode!
- 4
Juno: New Origins
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Indie and Simulation with Space Simulation Toolkit.
Bring to life anything you can imagine from rockets and airplanes to cars and more. Automate them with a visual programming language. Explore 3D planets and make your own. Share your creations online. Complete contracts, conquer milestones, and unlock technology in the newly added Career Mode.
- 5
Rocket Science
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Simulation and Early Access with Space Simulation Toolkit.
Take part in a space program. Design spacecrafts and send them off to explore the vast expanses of space. Experience the real scale of the Solar system and the size of its celestial bodies.
- 6
The Sapling
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Simulation and Early Access with Space Simulation Toolkit.
The Sapling is a short simulation game where you design your own plants and animals, and put them in a world together. Or you turn on random mutations, and see what evolution does to your ecosystem!
- 7
Terra Firma 2
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Indie and Simulation with Space Simulation Toolkit.
Shape breathtaking worlds in Terra Firma 2, a vast simulation where your creations evolve through the forces of nature. Sculpt the land, then watch as weather, erosion, and life itself transform your world into a dynamic, living ecosystem- right down to every plant and creature.
- 8
Kerbal Space Program
Single-player alternative to Space Simulation Toolkit — playable solo, no multiplayer required. Shares Indie and Simulation with Space Simulation Toolkit.
In Kerbal Space Program, take charge of the space program for the alien race known as the Kerbals. You have access to an array of parts to assemble fully-functional spacecraft that flies (or doesn’t) based on realistic aerodynamic and orbital physics.