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Squirrel's Pick Squirrel's PickThe best game on this page. If you only try one, try this. Budget Pick Budget PickThe best game here for the least money.
SpaceOpen WorldSci-fi
Monetized MonetizedHeads up: leans on microtransactions or free-to-play hooks.
Free ~69.7 hr median no co-op complexity: moderate 92.3% of 7k
The Squirrel's verdictFree and open-source, Endless Sky runs on a 2D top-down format instead of X3's 3D cockpit and dense station-to-station economy. The core activities carry over — trade, fight pirates, upgrade ships, build toward larger fleets — but reviewers consistently note a lighter entry barrier and less early-game grind. Median playtime is 69.7 hours. No co-op.
Not for you if you want X3's full 3D piloting and layered economic simulation rather than a 2D take on the genre.
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Base-BuildingSpaceColony Sim
$24.99 ~47.1 hr median no co-op complexity: moderate 85.8% of 11k
The Squirrel's verdictSpace Haven puts crew survival — managing power, food, repairs, and ship layout — at the center of its loop rather than sector-to-sector trade and fleet automation. Ship design is deep and engaging, but reviewers point to a demanding tutorial and an interface that takes real time to learn. Median playtime is 47.1 hours. $24.99, no co-op.
Not for you if you want open-galaxy trading and large-scale fleet management rather than a single ship's crew and internal systems.
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Closest Match Closest MatchThe most similar game to the anchor, by what players say.
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 swaps X3's real-time flight and manual piloting for turn-based travel and dice-based skill checks resolving combat, trading, and crew events. Same depth of overlapping systems - trading, smuggling, bounty hunting, fleet and crew management - but abstracted through RNG rather than direct control. Median playtime 70.9 hours; $14.99.
Not for you if you want direct real-time ship control rather than skill-check rolls deciding fights and trades, or you need recoverable difficulty after setbacks.
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Space SimSpaceExploration
$24.99 ~19.4 hr median co-op complexity: heavy 83.3% of 444
The Squirrel's verdictBuilt by a single developer, Evochron Legacy SE supports co-op, uses Newtonian flight physics, and lets players trade, mine, fight, and construct ships and stations in an open galaxy. The seamless planet-to-space transitions and deep manual flight controls are recurring highlights in reviews. Median playtime runs 19.4 hours. Price is $24.99.
Not for you if reviewers consistently describe the content as shallow despite the range of available activities
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SpaceExplorationTrading
Moral Weight Moral WeightHard choices with real consequences are central here. Strong Mods Strong ModsA deep, active modding scene extends it past its base content.
Free ~18.2 hr median no co-op complexity: moderate 80.7% of 228
The Squirrel's verdictNaev is a free, open-universe 2D game where players jump between systems, take missions, upgrade ships, and build a reputation across factions. Lore is detailed and the sandbox is genuine, though reviewers flag awkward engine balance, limited fleet options, and some quests that offer poor reward relative to effort. Median playtime is 18.2 hours.
Not for you if you want fleet command, capital-ship scale, or a universe built to absorb hundreds of hours of play
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Space SimSpaceAction
Free ~15.1 hr median no co-op complexity: heavy 79.2% of 337
The Squirrel's verdictHelium Rain centers on an interconnected economy where every ship's actions — hauling food, mining materials, fighting rivals — ripple through supply chains in real time. Newtonian flight physics and manual docking replace X3's autopilot-heavy scale, and the sandbox is compact rather than galaxy-spanning. Median playtime is 15.1 hours. Free, no co-op.
Not for you if you want X3's sprawling galaxy, deep faction sandbox, and hundreds of hours of content rather than a compact single-system economy.
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Sci-fiSpace SimOpen World
Moral Weight Moral WeightHard choices with real consequences are central here.
$14.99 ~17.9 hr median no co-op complexity: light 75.8% of 264
The Squirrel's verdictPlayers who want a quest-driven story alongside the usual trading, mining, and combat loop are Gaia Beyond's target audience. A scripted questline guides progression from the start, and the solar-system setting gives it a distinct backdrop. Reviewers flag buggy side quests and a half-finished feel despite the 1.0 release. Median playtime is 17.9 hours. $14.99, no co-op.
Not for you if you want an open sandbox with player-driven economic freedom rather than a structured, story-gated quest path
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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 trades X3's galaxy-spanning economy for a single ship you fly and crew directly: station assignments, manual combat maneuvering, and planet landings with ground fights. Median playtime sits at 9.1 hours, a fraction of X3's scale. Good fit if you want X3's crew-and-combat texture without the empire-building or automation loops.
Not for you if you want X3's long-term economic depth or fleet management rather than a single ship and crew