I'm not sure which impresses me more, how great Super Mario Odyssey sounds as a Mario soundtrack, or how great it would sound as a non-Mario soundtrack. On the one hand you've got excellently arranged classic Mario themes, Galaxy'esque new themes like "Fossil Falls", and lively big band pieces (including a surprisingly good English vocal) that fall right in line with the sound of the series. On the other hand you've got ethnic-accented town themes, atmospheric environment themes, and dramatic orchestral pieces that could easily pass for a JRPG soundtrack - and a very good one at that. There's even some hard electric guitars and traditional Japanese instrumentation and chanting thrown into the mix for the boss battles.
Whatever the sound, the musicianship of an expert live ensemble (and quality sound design on the synth side) permeates the score with an energy rarely found with such consistency in OSTs of this length. Only from the end of the third disc, when the less essential themes come into play, does the soundtrack fall a bit closer to normalcy, but at least they're relegated to the end for die-hard fans to enjoy without slowing down the main part of a great OST for the rest of us.