Free games like Mars Quest
Below are 9 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
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!
- 5
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.
- 6
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.
- 7
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.
- 8
Warframe
Free-to-play alternative to Mars Quest — no purchase or trial window. Shares Action with Mars Quest.
Awaken as an unstoppable warrior and battle alongside your friends in this story-driven free-to-play online action game
- 9
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).