Vibecoding a rhythm game for my synthwave album

Building a rhythm game out of my own album. First level is playable. Each song becomes a level with its own world. Beats on Maschine MK3, vocals generated in Suno, game is WebGL, mostly written with Claude Code. Two things took most of the time and neither was the graphics. First was tempo. Tap tempo put me nearly a full BPM off, which sounds like nothing until the notes are two seconds ahead of the music by the outro. So I measure it off the waveform instead, onset detection plus a least squares fit against the beat grid. Got it to 87.7636 BPM with almost no drift over the whole song. Second was the editor. Charting in raw JSON is awful, so I built a Studio: live game preview on one side, waveform and timeline on the other. Scrub to any beat, everything snaps to the grid, and you place notes and camera cuts while the song plays. Notes go in four lanes as taps, holds or slides, and the patterns follow the song rather than just the beat, so the chorus and the verse feel different…