The majority of music is worth listening to, though some tracks really stand out above the others, specifically the core character theme tracks. Most music sung by the LocoRoco is excellent while Mui Mui music tends to get annoying, though I understand how it plays a large part in the game. The "Mui Mui" sing any tracks that the LocoRoco don't sing with their helium filled voices. The album consists of several different singers who each represent a color of LocoRoco from the game. This is no Sims gibberish, but rather a full-fledged language that sounds just amazing when sung. The first thing you absolutely need to know about this soundtrack is that it's sung in a completely fictional language, which is appropriately called "LocoRoco Language". The soundtrack may not be for everybody, but most will at least be able to appreciate what went into it. They not only composed the music but also performed most of the instrumentals. Nobuyuki Shimizu and Kemmei Adachi, who are pretty new to the mainstream video game music crowd, composed the soundtrack.
Comparable or not, the LocoRoco soundtrack is, no doubt, completely unique in its own way. Some even compare it to Katamari Damacy's soundtrack, which is comparable in a sense because of certain elements they share such as children singing and zany arrangements.
The LocoRoco Original Soundtrack is simply one of the most creative and pleasurable game soundtracks to ever exist.