Overtone

Nothing in this game is a recording.

Every sound you hear is synthesised in your browser the moment you press a key. Hit the bass lane and the bass note fires — right then, at the moment your finger moved. Which means the song is only ever as tight as you play it.

The mix is your scoreboard

Four lanes: bass, drums, arp, lead. Play a lane well and its instrument comes up in the mix. Miss and it drops back out. Hold all four together and layers you never had to play bloom in on top — hi-hats first, then a chord bed, then a counter-melody.

Play badly enough and all that is left is a click track in an empty room.

Do not mash

A key pressed with no note under it is an overhit: it breaks your combo, costs points, drops that layer out of the mix, and counts against your accuracy. Hammering all four keys scores zero and silences the song. Playing is the only way through.

What is in it

• 12 hand-composed tracks, 84 to 150 BPM, each with a par grade to beat
• A daily track seeded from the date — the same one for everybody — with a streak counter
• Latency calibration, because browser audio timing varies by machine and you deserve to know it is not your fault

Controls

• Four lanes — D F J L
• Long notes are held down
• Pause — P · Mute — M

Touch works too: four zones across the bottom of the screen. Turn your phone sideways.

Calibrate first. It takes twenty taps and it is the difference between the game feeling tight and feeling broken.

How it is built

One HTML file. No engine, no asset packs, no network calls. The instruments are oscillators, the drums are filtered noise, the reverb is a generated impulse, and the font is a 5×7 bitmap drawn glyph by glyph. Notes are scheduled ahead on the audio clock, and the playhead you see is placed where the audio you actually hear is, so your eyes and ears agree.

It was built with the help of an AI assistant (Claude), which wrote the code, the compositions and the sound synthesis. Directed and tested by a human.

Free. The tip jar is right there if it earned one.