The gems

Gems slide down the neck toward the strikers, the coloured rings on the hit line. Press a lane's key when its gem meets its ring. Two gems side by side are a chord: press both.

Easy uses the first three lanes, Medium four, Hard and Expert all five. Change keys in Settings.

Timing

Heat

The gauge is the amp's temperature. Hits warm it, misses cool it. Let it fall to the bottom and the valve blows, which ends the song. Turn on No-fail in Settings to play through anything.

Burn

Gems with a gold edge are a burn phrase. Hit every one in the phrase to add a quarter to the Burn meter. At half full, press Space (or tap the meter) to light it: every point counts double until it burns out.

Duo

Two players, one keyboard or one screen. Pick Duo on the setlist: each player gets a neck, and on house tracks player 2 can take the bass part. You share one amp, so the heat gauge rises and falls with both of you, and your scores add up to one joint score with its own board.

Player 2's keys. On a touch screen, each player plays their own side.

Versus

Same two necks, but each player has their own amp and the higher score wins. If you pick different difficulties or parts, the winner is whoever gets closer to a perfect run. Blow your amp and you're out while the other player plays on. Versus runs don't go on the leaderboard; this device keeps the head-to-head count.

Strum

Pick Strum in Settings to play like a guitar controller: hold the fret keys (A S D F G) and strum with Enter, ↑ or ↓ as the gem crosses its ring. A chord needs exactly its frets. A single gem only needs its fret to be the highest one down, so you can keep lower frets held. Strumming with nothing to play is an overstrum, which breaks the streak on Hard and Expert.

Hammer-ons, taps and open notes

Gems with a white cap are hammer-ons and pull-offs. While your streak is alive, pressing or lifting a fret takes them without a strum. Dark gems with a coloured ring are taps: fretting takes them, streak or not. A purple bar across the neck is an open note: strum it with no fret held. In press mode, any key with nothing of its own to hit takes an open note.

Whammy and solos

Bend a held gem from a burn phrase with whammy (Right Shift in strum mode) and the Burn meter fills while you hold it. In a solo, the meter at the far end of the neck counts your hit rate; at the end each note hit pays a bonus, doubled if you hit them all.

Stars

Stars measure your score against a perfect run without burn. A perfect run earns five; burn makes up for a few misses.

Your own songs

Riffraid charts a song from its sound: onsets for the notes, the beat for the grid, each note's pitch for its lane, so the same note tends to sit in the same lane. Songs with a clear beat chart best. If notes feel early or late on every song, use Calibrate in Settings.

Or load a chart folder: a song someone charted by hand, in the community format (notes.chart or notes.mid with the song's audio). It plays exactly as charted, with its own difficulties, hammer-ons, taps, open notes, burn phrases and solos, and the bass part when the folder has one.