Imagine building a complex customized level in Super Mario World, then synchronizing every sound effect of the game (the sound of a power-up, an enemy stomp, yoshi, eating a mushroom, etc) and the timing of Mario jumps with absolute precision, all of this to make them sound like a song; actually like a lot of songs! (mostly anime songs though). As the description of the original video says:
Please enjoy!"Countless koopas were damaged in the production of this film"