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Squirrel's Pick Squirrel's PickThe best game on this page. If you only try one, try this.
Space SimEconomySpace
$49.99 ~167.4 hr median no co-op complexity: heavy 79.9% of 29k
The Squirrel's verdictX4: Foundations scales the systems-over-story sandbox to economy-wide simulation: trading, fleet building, and station ownership across a persistent galaxy. Where Ostranauts keeps you inside one hull managing individual components, X4 zooms out to sector-spanning logistics. Released in 2018 and updated through at least 2026, its core loop is functional—though tutorials operate as a separate manual rather than connected gameplay.
Not for you if you want tutorials that connect to actual gameplay instead of a separate manual you consult mid-run.
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Closest Match Closest MatchThe most similar game to the anchor, by what players say.
Base-BuildingSpaceColony Sim
$24.99 ~47.1 hr median no co-op complexity: moderate 85.8% of 11k
The Squirrel's verdictSpace Haven shares the core premise: build a ship piece by piece, salvage to keep crew fed and powered, and watch small oversights cascade into hull failures. It scales that loop up to multi-crew colony management rather than a single character in a suit, carries a Very Positive rating, and reached a 1.0 release in 2026. The UI is widely flagged as a friction point, and the tutorial is effectively mandatory.
Not for you if you want the solo, one-body-in-a-suit intimacy of Ostranauts rather than juggling a crew, or you can't tolerate a rough UI and mandatory tutorial.
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Budget Pick Budget PickThe best game here for the least money.
Sci-fiTactical RPGTrading
Strong Mods Strong ModsA deep, active modding scene extends it past its base content.
$14.99 ~70.9 hr median no co-op complexity: heavy 83.6% of 4k
The Squirrel's verdictStar Traders: Frontiers carries a Very Positive rating and a median playtime around 71 hours, built on dense overlapping systems: crew management, trade routes, skill checks, and permadeath consequences across a galaxy at war. It trades Ostranauts' tactile inventory-and-hull simulation for text-and-stat-driven crew management, where RNG skill rolls decide most outcomes.
Not for you if you want hands-on ship-system tinkering over stat-driven crew management, or dislike heavy RNG skill checks deciding outcomes.
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ExplorationColony SimBase-Building
Strong Mods Strong ModsA deep, active modding scene extends it past its base content.
$29.99 ~53.8 hr median no co-op complexity: heavy 87% of 2k
The Squirrel's verdictStardeus centers on automation and research: colonists handle logistics through queues you configure, and a tiered research tree gates most basic ship functions. That structured progression trades Ostranauts' freeform derelict-scavenging for something closer to RimWorld in space, with base-building depth and developer transparency reviewers note as a consistent strength.
Not for you if you came for Ostranauts' loose, hands-on inventory tinkering rather than research queues and automated colonist logistics.
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SpaceSci-fiBase-Building
$19.99 ~29.2 hr median no co-op complexity: moderate 75.4% of 2k
The Squirrel's verdictThe Last Starship puts you designing and maintaining a ship at the component level, with combat and crew survival tied to how well it holds together. It expands scope toward colony and fleet management rather than the single-hull scavenger loop, drawing comparisons to Cosmoteer and Stardeus. It reached 1.0 in 2026 with a Mostly Positive rating, though reviewers flag thin endgame content.
Not for you if you want the tight, one-ship, one-body survival focus rather than a broader colony and fleet-management scope.
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Space SimEconomySci-fi
$29.99 ~23.6 hr median no co-op complexity: moderate 74.7% of 2k
The Squirrel's verdictStarminer shares the ship-systems focus: Newtonian physics, building and managing your own vessel, flight and combat as separate learned systems rather than abstracted menus. Where Ostranauts is single-ship survival and inventory management in a derelict, Starminer leans toward building, mining, and drone management with a tech tree. Fits players who want ship engineering over narrative scavenging.
Not for you if you came to Ostranauts for the scavenging and inventory-survival loop rather than base-building, mining, and tech-tree progression.
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Interstellaria
PCMacLinux
SpaceExplorationDiplomacy
$9.99 ~9.1 hr median no co-op complexity: moderate 55.9% of 410
The Squirrel's verdictInterstellaria shares the crew-and-ship management fantasy: assign stations, keep systems running, explore derelicts and planets for salvage. It trades Ostranauta's granular inventory-and-hull simulation for structured FTL-style combat, an actual plot, and a defined endpoint at roughly 9 hours median playtime, with less freeform system depth but a shorter, more finished loop.
Not for you if you came to Ostranauts for open-ended systems simulation rather than a guided campaign with combat and a story to finish.
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TradingSpaceEconomy
$9.99 ~12.8 hr median no co-op complexity: light 48% of 1k
The Squirrel's verdictCosmonautica runs a Sims-in-space loop: hire crew with individual traits, open trade routes, upgrade your ship, and manage personalities alongside cargo. It's shallower than Ostranauts—roughly 13 hours of content—and the economy has documented bugs, including static markets that cap out and strand purchased goods. The developer has stated no further patches are planned.
Not for you if you want deep systemic simulation and inventory-level ship management rather than a lighter trade-and-crew loop.