The entire soundtrack for the anime is filled with glorious tunes taken from various genres, ranging from classical to techno.
- Both the opening
and closing themes are incredibly catchy. Someone even made an 8-bit version of the opening song less than a week after it premiered, and then a Eurobeat version drifted into existence. There's a Village People mashup version, as well as an English fandub. - "Declaration" is a pretty badass song, sounding like it'd be right at home in a high fantasy action scene. Which makes it all the more hilarious that it's being used to underscore the gang rating their time boning cyclopes.
- "Smokey Review" is widely considered the best tune on the entire OST and for very good reason. It often plays when the crew are getting down and dirty with their companions for the evening and manages to set the mood perfectly every time it's played. Sleazy and dirty... yet somehow refined and sophisticated at the same time, like a mix between a smokey bar and an upper class cocktail lounge in terms of sound. And that piano! Dang! Forget the monster girls, nudity and fetishes... THIS is the true Fanservice of Interspecies Reviewers!
- "Psyched" is another fantastic song that plays when the group brave the lilim horde. It manages to sound playful, perverted... psychotic... all at once. Quite the fitting choice for this particular ahem "raid boss" by the composers.
- "Marionettes" sounds like some of the most wonderfully demented circus music ever and is a perfect fit for the strange and whimsical golem brothel the reviewers visit in episode 6.
- "Parade" is a fantastic happy-go-lucky piece that perfectly captures the mood of the visually stunning light parade that occurs after the reviewers visit the light spirit brothel. A true feast for both the eyes and the ears.
- "Sorrowful Fist" honestly doesn't even sound like the type of song you'd expect to see in an anime at all, especially a silly sex comedy like Interspecies Reviewers... but listeners will certainly be very glad to hear it anyway! Another shining testament to the brilliant sound crew and composers.
- The Beginning serves as the musical introduction to the very first scene of the series as it plays over an awesome narration describing the world and the many fantasy races that inhabit it. It wouldn't be out of place as the opening track of some epic high fantasy saga... which almost makes it a shame that it's used to introduce a series focused entirely on magical brothels and monster girl sex workers. Almost.
- Pinkish Illusion is another classy jazzy sort of piece that lends a distinct sort of old timey feel to the soundtrack kind of like what you might expect to see in an old detective noir or romance film. The fact that it's instead used to introduce a couple of undead prostitutes is just the icing on the cake.
