This article has a talk page!This page details pre-release information and/or media for Maestro! Jump in Music.
Watch on YouTubeWatch on YouTubeThe main developer of this game shared footage of the game pre-release, which features some different looks compared to the final release.
First of all, the name was Jumping Music DS, as we can see in this advertising, which is also in the first video, and it mentions "Single-card multiplayer modes inside!" and a "Beat-box" mode, neither of which ended up in the final release. 
The menu used a record player back in this prototype as well, however it is clearly more funky-looking and bright than the final one, which looks more classical. The options are also "Play", "Chapters", "Vocals" and "Free Play". Clicking on "Chapters" leads to three different worlds, each named "Baroque", "Romantic" and "Tropical", and each seems to only have 2 tracks, which are also referred to as "Dreams" here. Baroque, Romantic and Tropical would end up becoming respectively Purple Sonata, Yellow Allegro and Green Groove, however their prototype design is the same as the final.
The core gameplay itself is the same as the final. Some notable differences, however, are still present. Pick-up objects had a glow around them, the notes had a vertical glow which applied to the whole string, changed to be a shrinking horizontal glow in the final, the circles around enemies started with a very large size, the vortex in the Black Out Beats levels also appeared to look more stylized and less realistic, the rabbit enemies had a different animation where they would zoom into the screen and be slightly rotated, whereas in the final they just come from off screen without any special animation, some pick-up objects in the space level also used to be asteroids, which sprites remain in the files, the Yellow Allegro levels also use the space star pick-ups instead of the final tomatoes, the SFX for dropping down/jumping are also different, sounding more like a cartoon spring than a string, the blue notes look like the gold notes but blue, instead of being a quarter note, when stringing a harp a triple note comes out, and the enemy spiders also have a more static animation.