Here's a video of a mechanical piano performing Circus Galop (sic), a composition created to test the performance of automatic pianos and other instruments. It apparently can't be played by humans. a single, two-handed human.

Circus Galop is a piece for player piano written by Marc-André Hamelin. It was composed between 1991 and 1994 and it is dedicated to Beatrix and Jürgen Hocker, piano roll makers. Its duration is approximately 4–5 minutes.[1] Scores of this piece are available through the Sorabji Archive.[1] Piano rolls of this piece are available from Wolfgang Heisig and Jürgen Hocker, who have recorded all three of Hamelin's player piano pieces on the MDG label and were released in April 2008.[2][3]

It is not possible to be played by humans, as at some points all the piano staves are played at the same time, and up to 21 notes simultaneously. It is used to test MIDI software to drive it to its maximum potential, such as Synthesia, or PianoMIDI.[4]