R$1 — One Real

A one-screen game built on a real piece of physics.

Spin a coin on its edge and it doesn’t just slow down — it tips over, and as it tips the wobble gets faster. That rising rattle a coin makes right before it settles is the Euler disk effect, and it’s the whole difficulty curve of this game. Nothing here speeds up because a designer decided it should.

The coin is a Brazilian 1 real: bimetallic, stainless steel core inside a bronze-plated ring, 27 mm across and 1.95 mm thick, with the interrupted milling on its edge. Tap when it passes upright and you flick it back into balance. Tap off-beat and you make it worse.

Every good flick is worth 5 centavos, and the score is counted in reais — so the whole game is about earning back the real you spent on it.

Install it on your phone: (link do GitHub Pages depois do deploy) — same game, adds itself to your home screen and runs offline.

• One tap, no menus, about a minute a round
• 10 languages, switchable in-game
• Companion piece to 1円 — One Yen: that coin has to land flat, this one has to stay upright