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Squirrel's Pick Squirrel's PickThe best game on this page. If you only try one, try this.
Base-BuildingSpaceColony Sim
$24.99 ~47.1 hr median no co-op complexity: moderate 85.8% of 11k
The Squirrel's verdictSpace Haven builds its management loop around a ship that actively decays: power, food, and repair materials all deplete in real time, so neglecting any system triggers cascading failures. You design ship layouts and manage crew rather than racing rival agencies through historical milestones. Reviewers consistently flag the UI as a significant friction point even after extended play.
Not for you if you want turn-based milestone-racing against rival agencies rather than a real-time crew and resource sim with a UI reviewers call difficult to navigate.
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Grand Strategy4XHistorical
Strong Mods Strong ModsA deep, active modding scene extends it past its base content.
$39.99 ~177 hr median no co-op complexity: heavy 80.5% of 9k
The Squirrel's verdictBoth put you in charge of a space program racing rivals through tech trees and mission planning rather than hands-on piloting. Terra Invicta trades Mars Horizon's streamlined agency choices for a sprawling geopolitical layer: recruiting councilors, influencing nations, fighting aliens across a much deeper, longer campaign at median 177 hours.
Not for you if you want Mars Horizon's clear, guided structure rather than a sprawling system with a poor tutorial and a UI reviewers call punishing to learn.
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Procedural GenerationSurvivalRogue-like
$19.99 ~48.4 hr median no co-op complexity: moderate 88.4% of 4k
The Squirrel's verdictDeck-building and roguelike structure drive Terraformers: each run randomizes available cards, meta-progression unlocks new buildings between runs, and a rising dissatisfaction meter forces a race to the objective before it caps out. There are no rival agencies and no historical timeline — Mars colonization is managed through card choices and resource decisions across runs reviewers clock at roughly 90 minutes each.
Not for you if you want a historical campaign or slower city-builder pacing rather than card-based runs with a mechanic that punishes stalling.
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Hidden Gem Hidden GemLoved by the players who found it, but still under the radar. Budget Pick Budget PickThe best game here for the least money.
Solar Expanse - Space Exploration Manager
PC
SpacePhysicsScience
$17.99 ~34.4 hr median no co-op complexity: moderate 88.1% of 1k
The Squirrel's verdictWhere Mars Horizon follows a fixed historical milestone ladder, Solar Expanse opens into a logistics network: haul resources between planetary bodies, build outposts, and expand toward terraforming across a persistent economy with no scripted endpoint. Reviewers note sparse ledgers and a clunky transportation system alongside genuine depth for players who want open-ended resource management over a longer, less directed campaign.
Not for you if you want polished progression and accessible information displays rather than an open logistics system with UI gaps and limited resource tracking.
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Closest Match Closest MatchThe most similar game to the anchor, by what players say.
SpaceCompetitiveSpace Sim
$19.99 ~9.8 hr median no co-op complexity: light 87.7% of 913
The Squirrel's verdictPlayers who want agency management without rival-agency pressure or historical scripting will find EarthX's single SpaceX-style company loop approachable: contracts, orbital logistics, and upgrades drive progression. Reviewers describe the core as clicker-adjacent — money funds upgrades that enable more money — with contract negotiation replacing any milestone race. Median playtime is under 10 hours.
Not for you if you want agency variety, historical milestones, or rival competition rather than a short single-company upgrade loop reviewers compare to a clicker.
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Space SimSpaceExploration
$24.99 ~19.4 hr median co-op complexity: heavy 83.3% of 444
The Squirrel's verdictMars Horizon manages a space agency from menus and cutscenes; Evochron Legacy SE puts you in the cockpit with Newtonian flight physics, trading, mining, and combat across a persistent open world. Both are space-themed strategy-adjacent games, but Evochron trades turn-based milestone planning for direct piloting, ship building, and real-time missions.
Not for you if you want Mars Horizon's guided historical structure rather than an open-ended sim with a long tutorial and self-directed goals.
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Buzz Aldrin's Space Program Manager
PC
SpaceCold WarHistorical
$29.99 ~34.3 hr median no co-op complexity: moderate 76.9% of 497
The Squirrel's verdictSame space-agency management core as Mars Horizon: pick milestones, manage research and launches, watch named crew risk death on faulty hardware. BASPM narrows to two agencies (US/USSR) but adds real historical branching paths and part-level reliability tuning. Mission outcomes lean harder on probability rolls, and failures often arrive without explanation, so recovery from a bad streak is harder than Mars Horizon's milestone race.
Not for you if you want failure causes explained rather than opaque probability rolls, or want more than two playable agencies.
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RPGSpaceBase-Building
$9.99 ~10.9 hr median no co-op complexity: moderate 69% of 329
The Squirrel's verdictThe Spatials replaces historical milestone racing and rocket launches with space-station base-building, real-time tactical combat missions, and crew micromanagement across planet visits. The strategic decision layer is present, but reviewers note shallow difficulty and a grind-heavy resource loop. Median playtime runs around 11 hours, shorter than most agency management games.
Not for you if you want historical space-race structure or meaningful difficulty rather than base-building with light combat and a grindy resource loop.