Idol Showdown is based on an idol company, so of course this fangame is going to have banger music.
- The main theme
of the game is a high-octane rock track that gets you into the spirit of a Hololive fighting game. - "Nousagi Jazz Band" is a swinging jazz cover of "PekoRandom Brain" by Usada Pekora, playing into her mischievous and chipper personality.
- "Shrine of the Elite" is used in several of the game's trailers, and usually plays in the Moonlit Gates stage. As a remix of "Kagetsu no Yume", it really gets you hyped up for a match, especially with the traiditional Japanese instruments placed about.
- "Blood Lust", from the Moonlit Gates stage, is a pulse-pounding electronic remix of Mori Calliope's "RED" that guarantees to add intensity to any match where it plays.
- "Midnight Rose" recontextualizes Aki's signature "Shallys" into the theme of a literal bar fight thanks to an increased tempo and the addition of a driving acoustic guitar melody.
- "Megalodon" takes Gura's "Reflect" and converts it into an energetic sea ballad fit for a cruise atop the AquaMarine.
- Once you reach the end of the Arcade Mode, you're met with "Final Showdown", the mode's Final Boss theme. Clearly recognized as "Shiny Smily Story", and yet extremely glitchy, off-beat, and generally ominous, the message is clear: whatever it is you're facing there, it is not Sora.
- "A New Journey" is the slow, calm version of "Astrogirl" that plays in the Virtual Frontier. It becomes progressively more complex before you start hearing not only the now-graduated Tsukumo Sana singing, but all of Council.hamslyx: Fun fact about this track! The vocals heard on stage 3 are not just Sana. I compiled every recording of the song I could find and layered them all together! So all the girls are singing at once here!
- The Next Fes update adds three new bosses to Virtual Frontier, each with some bangers for their leitmotifs.
- "Kon Kon Beatdown", the theme for Kurokami and Fubzilla, adapts "Kon Kon Beats" into a climactic battle theme with ominous chanting.
- "Time of Death", the theme for Kronii, is a melodic take on "Daydream", with clock-ticking accompaniment to make a theme suitable for the warden of time herself.
- "Flayon X Showdown", the theme for Flayon in the R-TRUS, is a high-octane spin on "DEAD WORLD", with the energy to match a battle with a Humongous Mecha.
- "Kon Kon Beatdown"
