A mix of Atari Crystal Castles + gameplay tribute element of Stern's Berzerk.
Some of the musical medley pieces are very good. On some of the instrument pieces, the music audio seems to have had real musicians in a recording studio (doing drums and xylophone or marimba) being sampled. The xylophone or marimba sounds (round 1 and 2) seem to have a better quality compared to what would have been generated from a keyboard synthesizer back in the 1990s.