Twenty fights, twenty tracks, no server of mine

A free neon boss-fight game for iPhone, iPad and Android. Hold your thumb on the orb to move it, lift to strike. When you lift decides whether it lands, and the longer you hold, the harder it hits. It’s on Google Play now and coming to the App Store. The app page has the details.

• Timing locked to real music.Each of the twenty fights has its own track and its own chart. The game syncs to a beat map built ahead of time, against the audio playhead, and never uses real-time beat detection.
• Coins that follow you, with no server of mine.Coins live in the player’s own iCloud on Apple devices and in Play Games Saved Games on Android. They follow you between devices of the same kind; on Android that takes a Play Games sign-in. My first design kept the record in one shared iCloud key, where two devices writing at once could lose a grant. So I redesigned it around one key per device on Apple: each install writes only its own key and reads everyone’s. By design, no device can overwrite another’s record.
• Little to collect.No analytics, no ads, no crash SDK, no account with us, no server of ours. Scores and coins go to Apple or Google. All I see is what their developer tools show me: crash reports you choose to share, and a leaderboard’s top scores.
• I wrote the music.All twenty tracks, written and produced by me. It’s also why the charts fit the music: the same person made both.

If your app has to keep time with something, or keep data consistent across a person’s devices, those are the parts that break. I try to remove a server before I secure one.

Related: web apps and custom software.