Free online browser games with no signup, no download, and no payment required
A hard sci-fi idle game evolving from the Big Bang to an interstellar civilization
Stage
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Founded
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Based in
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Pricing model
Free
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
Memory games like Memory Grid and Missing Object
Timing and prediction games
Puzzle and deduction games
Classic games including 2048, Sudoku, and Solitaire
Strategy and competitive games
Arcade-style games
Daily challenge with shared worldwide puzzles
Local score saving without account
Touch-optimized mobile play
Share scores with friends
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
Completely free with no unlockables, paid tiers, or in-game purchases
No signup, login, or app download required
Plays on mobile and desktop identically
Most games completed in under a minute
Scores saved locally between visits without account required
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
PlayDash.gg
Cosmos Era