Making a high intensity music game inside of a web environment is quite the challenge. Especially if it features songs with high difficulty and pacing.

Using PixiJS as a graphics library, I built a custom class that would register touch events on the microsecond, register the finger position. The song note data will be compared to the input data with a delay margin (using Bluetooth headsets will have a 100ms to 300ms delay in audio). This makes input time extremely accurate, and has the added benefits that the song time could be rewound or moved anywhere and replayed. The input data is also used as verification to detect bots or hacks.

It was a lot of fun building this, and seeing it working well on different mobile devices.