Only the most musically adept among you will be able to define what is sinister about this music.
The piece is by Maurice Ravel, which probably doesn't help much. It's played by Paul Wittgenstein, which might help.
Listen for a couple minutes before seeing the answer below the fold.
Wittgenstein is playing only with his left hand.
He studied with Malvine Brée and later with a much better known figure, the Polish virtuoso Theodor Leschetizky. He made his public debut in 1913 and favourable reviews were written about him. The following year, however, World War I broke out, and he was called up for military service. He was shot in the elbow and captured by the Russians during an assault on Poland, and his right arm had to be amputated.He commissioned this and other works:
Following the end of the war, Wittgenstein studied intensely, arranging pieces for the left hand alone and learning the new composition written for him by Labor. Once again he began to give concerts, and became well known and loved. He then approached more famous composers, asking them to write material for him to perform. Benjamin Britten, Paul Hindemith, Alexandre Tansman, Erich Wolfgang Korngold, Sergei Prokofiev, Franz Schmidt, Sergei Bortkiewicz, and Richard Strauss all produced pieces for him. Maurice Ravel wrote his Piano Concerto for the Left Hand, which became more famous than any of the other compositions that Wittgenstein inspired. But when Wittgenstein made changes to the score for the premiere, Ravel became incensed and the two never reconciled.Wikipedia has a page listing works for the piano left hand and orchestra. There are over 40 of them, but - surprisingly (to me) - only four composed for the right hand only. Why the discrepancy ??