Free games like Mars Quest
Below are 10 free-to-play Steam games similar to Mars Quest, ranked by player overlap and content similarity. No purchase or Steam login required to view the list. Every pick is a full free-to-play title — not a demo, trial, or time-limited giveaway. imho.run's catalogue refreshes daily, so newly free or newly popular titles surface here without manual editing.
Want the full alternatives list (paid + free + Steam Deck + cheaper picks)? See the parent games like Mars Quest page.
Ranked picks
- 1
STRAFTAT
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action with Mars Quest.
STRAFTAT is a 1v1/2v2 ONLINE first person SHOOTER with quick rounds in over 350 MAPS ; Including all WEAPONS, proximity chat and 4 players FFA.
- 2
Counter-Strike:Global Offensive
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action with Mars Quest.
Counter-Strike:Global Offensive (CS:GO) expands upon the team-based action gameplay that it pioneered when it was launched over 2 decades ago. CS:GO features new maps, characters, weapons, and game modes, and delivers updated versions of the classic CS content (de_dust2, etc.).
- 3
The Lab
Free-to-play alternative to Mars Quest — no purchase or trial window.
Welcome to The Lab, a compilation of Valve’s room-scale VR experiments set in a pocket universe within Aperture Science. Fix a robot, defend a castle, adopt a mechanical dog, and more. Still not sold? It’s free!
- 4
Aircar
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Indie and Casual with Mars Quest.
A simple immersive flying game built for VR. Pilot an aircar through a futuristic cityscape.
- 5
I MAED A GAM3 W1TH Z0MB1ES 1N IT!!!1
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action and Indie with Mars Quest.
A top down twin stick zombie slaying shooter that you are sure to play again and again!
- 6
South Scrimshaw, Part One
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Indie and Casual with Mars Quest.
South Scrimshaw is the story of a newborn whale in a vast alien ocean. It is a richly illustrated experimental visual novel, written in the style of a nature documentary.
- 7
Wires And Whiskers
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action and Indie with Mars Quest.
Wires and Whiskers is a local co-op action-puzzle game where two players control a lab-engineered gerbil and its magnetic exosuit. Work together to fight mutated enemies, solve magnetic puzzles, and survive in a ruined, post-apocalyptic trench world.
- 8
Tom Clancy's Rainbow Six Siege
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action with Mars Quest.
Rainbow Six® Siege is the reference in tactical team shooters, where elite strategy and execution triumph. Enjoy free access to Quick Match, Unranked, and Dual Front game modes with a selection of operators.
- 9
WinBolo
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action and Indie with Mars Quest.
A multiplayer top-down tank game for up to 16 players. Capture bases and pillboxes, harvest trees, build roads and walls, lay mines, and battle for control of the island. The Macintosh classic, rebuilt for modern platforms — free, open source, and cross-platform across desktop, mobile, and web.
- 10
Retro Commander
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Indie with Mars Quest.
Retro Commander is a post-apocalyptic real-time strategy wargame (RTS).