Play checkers online free against the computer or a friend in your browser
A hard sci-fi idle game evolving from the Big Bang to an interstellar civilization
Stage
Not given
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Founded
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Based in
US
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Pricing model
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Freemium
Pricing
Not given
Free with no ads; optional Supporter: $2.99/mo, $19.99/yr, or $29.99 lifetime; time crystal packs: $1.99 (Skip a night), $4.99 (Skip a wall), $9.99 (Skip a week)
Key features
Play against computer with three difficulty levels
Play with a friend online via shareable link
Two-player mode on same device
Undo and hint system
Works offline after initial load
No downloads or plugins required
13.8 billion year cosmic timeline from Big Bang to interstellar civilization
118 sourced research cards with scientific citations
12 game eras spanning Cosmos, Life and Civilization
16 different endings
12 civilization channels inspired by science fiction and real concepts
Playable on phone, desktop and iPad with cloud save sync
Installable on phone home screen for offline play
No ads and completely free to play
1,400+ nodes each grounded in real science with sources
Physics-accurate simulation where 1 light-year equals 1 real hour
What makes it different
No account, download, or payment required to play
Works in any modern browser without Flash or extensions
Plays offline after page loads using service worker
Every scientific claim cites real sources with year, researcher and publication
Hard sci-fi design where physics and signal times follow real scientific laws
Completely free with no ads, payment optional and never pay-to-win
Invented game lore clearly separated and labeled apart from real science basis
Curated collection of 24+ open-source astronomy, physics and biology projects
Checkerso
Cosmos Era