Glitchstep

You are not losing hit points — you are losing the ability to see. Notes fall on two lanes and you hit them on the beat; every one you miss damages the presentation instead of a health bar. Sprites tear, the colour channels separate, the background freezes and jumps, the readouts garble. Play well and the picture is clean and sharp. Play badly and the game visibly falls apart around you.

How it plays

• Two lanes, two buttons, three note types. Taps, sustained holds, and doubles that need both lanes at once. Timing windows are deliberately generous — plus or minus 45 ms for a Perfect — because the punishment here is visual, not binary.
• Corruption is the health bar, rendered as damage. A miss adds nine, a Perfect takes two back, and it decays while you are clean, so a good run visibly repairs the picture in front of you. Hit 100 and the signal is lost.
• The lanes never corrupt. Everything else may fall apart, but the two lanes and the hit line are drawn on their own uncorrupted layer, and the severity of every effect caps below its maximum. A pause-menu toggle halves all of it again.
• The charts come from the music, not from a dice roll. Three synth tracks are generated at load, and each one emits the beat map that produced it — so every note sits on something you can actually hear, and the game asserts no two notes on one lane fall closer than 110 ms.
• Calibration first. Six taps measure your browser's audio latency before track one, because a rhythm game that has not measured your machine is guessing.

A near-black plate, one cyan lane and one magenta one, and a picture that is only ever as clean as your last thirty seconds of playing.