Find the crosses hidden in the colours — and unbuild them in reverse.
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
Freemium
Freemium
Pricing
Free with ads; premium one-time purchase removes advertising and unlocks larger boards.
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
Reverse-order puzzle solving with visual stack unwinding
Budget-based scoring system with vessel metaphor
Two-tap control interface with visual feedback
Difficulty selection with variable cross counts
Musical scale progression during gameplay
Hint system with cross visualization
Six language interface support
Interactive help tour
Adjustable board size for varied challenge
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
Plays the game's deal sequence backwards as sound when solving
One-time purchase with no subscriptions or additional in-app purchases
Score system uses visual vessel metaphor instead of climbing counter
Clean minimalist UI with readable typography and strong UX
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
Cosmos Era