TOUCH

Slide a thumb anywhere; MOP-13 moves with it. Fires while any finger is down. A second finger opens a purge valve.

MOUSE

Point to steer. Left button fires. Shift opens a purge valve.

KEYS

WASD or arrows. Space fires. Shift opens a purge valve.

MOP-13 cannot leave the bottom of the hall — it was assigned this floor.

FULL SCREEN

The hall fits the screen: a wide floor on a desktop, with MOP-13 bigger and quicker to match it, and a tall one on a phone with everything a size up.

CLASSIC

The original 20-column hall on every screen, at its original sizes and speeds.

Changing it rebuilds the hall. Each hall keeps its own high scores.

STANDARD

This hall's own: quicker every act, quicker again for the last few left, and a chain cut in the middle runs hot from the cut.

1981

Centipede's: two speeds and nothing else. The body crawls or it is quick, and every head is quick.

A switch for playing the two against each other. It changes the chain and nothing else, and it takes effect on the next shift.