It's a challenge that I found interesting because it allows you to step out of the comfort of using multiple instruments with a wide sound palette. What about using a piano or orchestral instruments on an analog synth, for example? It also forces to make the most of a single instrument.

The structure of the tracks remains identical to the original versions. The arrangement (orchestration) should also be as faithful as possible, without any additions or rewrites of the original parts. I only allow myself a few "small" adaptations when necessary.