Rules

Drop the next token. Tap a column, or press 1–4.
Match symbols to clear pads. Pairs connect across or down. Diagonals need three. A line of three can hook one more off either end. Falling pieces chain.
Hold a tile. Tap the Hold slot at the end of the queue to park the tile in hand, or to swap the parked one back in. Once a turn.
Closed columns take matches from above. When a column's bottom three pads are drums or Xs, drop the parked token's kind on it: the token lights 2, 3, then 4 and locks. Parked tokens of one kind side by side share the count.
Every four changes locks a drum. Each clear after the first changes the current drum. Locked drums keep playing.
Drop your locked drums. Clear beneath them for +500 each. Sixteen pads of drums and Xs close the machine.
Play each token before the count runs out. Time up drops an X into your last column. Tap the screen to pause.

The symbols

Double: Add in-between pulses.
Add: Add supporting hits.
Subtract: Strip back or soften the groove.
Special: Match two to change the current drum.
FX: Send the current drum to the room, the drive bus or the delay, or sweep the mix.
Wild: Takes the kind of its best match. A clear of three or more with a Wild pays triple. On the last open pad it closes the machine.
Lock: Locks the pad it lands on, and every touching token of the kind it lands on.
Swap: Tap to blink, then tap another tile. Swap disappears; tiles above fall.
Bomb: Every token around it clears, diagonals too, for 200 each. Never a drum, never an X.
Drill: Goes straight down a column, full or not, and clears every token in it. Drums and Xs stay. Pays nothing.
Money: Plays exactly like a Wild and pays 1000 when it lands.
Locked: A locked drum keeps playing and no symbol changes it. Locks come from the Drums tab, and from the drums you lock in a run.

Scoring
Match or bonus	Points
Initial pair	+25
Extra pair in a chain	+100
Snake or group Three or more of a kind	+100 per token
Lock a drum Extra for each drum	+25
Drop a saved drum Extra, once per drum per move	+500
Drop a token Each ordinary token that falls when you clear beneath it	+50
Contact on a closed column The count it lights: 2, 3 or 4	+25 per count
Money	+1000
Wild on the last open pad	+500
Bomb Each tile it clears	+200
Full house Every pad a drum; an X counts a quarter	+5000
No match	0
Chain reaction The move's points, times the number of clears	×2, ×3…

+300+500+100= 900 ×2

Later stages pay more: every amount is scaled by the stage, up to ×2 in the last four. Every match in a chain scores, then the chain multiplies the move: two clears double its points, three triple them. A snake counts each cleared token once. Newly locked drums earn the lock bonus; their fall bonus starts on later moves.