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The Humble Store has a Space Weekend Sale going on.
Endless Space Gold $8.74 (Steam)
Space Pirates and Zombies (S.P.A.Z.) $2.49 (Steam, DRM Free)
Sins of a Solar Empire: Rebellion $13.32 (Steam)
Galaxy on Fire 2 Full HD $4 (Steam)
Interstellar Marines $14.24 (Steam)
Starpoint Gemini 2 $10 (Steam)
Space Hulk $7.49 (Steam)
Galactic Civilizations II: Ultimate Edition $5 (Steam)
Universe Sandbox $2 (Steam, DRM Free)
Horizon $12 (Steam)