Tangentfall

The problem

Calculus 1 is where a lot of engineering students first hit a wall. Practice problems feel abstract, and nothing makes you want to do one more. I wanted practising to feel like a game you would pick up anyway.

What I built

Tangentfall is a 3D action RPG where every node on the campaign graph is a Calculus 1 skill guarded by a sentinel. Correct answers slash it apart, answering within six seconds lands a critical hit, streaks multiply damage and fill a Limit gauge, and wrong answers cost one of three shields. Bosses guard each chapter, missed problems come back so you actually learn them, and a new Daily Rift opens every day.

The game is built with three.js and GSAP and bundled with esbuild into a single app that makes no network requests, so it loads instantly and works offline.

The same build ships three ways: as native iOS and Android apps through Capacitor, as an installable web app, and as a free early-access edition at play.tangentfall.com. The web edition runs on a Cloudflare Worker with a D1 database that keeps anonymous play counts and runs a price test.

What I learned

• Shipping one codebase to the web, iOS and Android, and what app stores expect from a game built on web tech.
• Building fully offline by bundling every library, font and asset, so the game never needs the network.
• Measuring real interest with anonymous counters and a price test before deciding what to charge.