It was later re-released in 2003 as JumpStart Advanced 1st Grade: Music.
Hopsalot gets transported to the Land of Music, where the villainous Sir Sournote has soured all of the musical notes. Hopsalot must collect the soured notes and bring them to the Concert Hall to make them sweet again.
Travel around the Land of Music and play different activities to find sour notes. Move Hopsalot down the roads of the Land of Music with the mouse. When Hopsalot is next to an activity spot, click on it to play the activity. When you successfully complete an activity, you'll find one or more sour notes. Catch the sour notes and put them in the bag. When you have found all of the sour notes in an activity spot, a red glow appears around it. If an activity spot is glowing green, that means there are still sour notes to be found there. After you find all of the sour notes, take them to the concert hall to restore them to their original state and make the music sweet again.
- Find the Sour Notes - First, listen to a song. After the song finishes, sour notes will invade the song. Listen to the song again, and find the musical notes that aren't right. You can click on the monkey to hear the correct version of the song again, and you can click on the Hornbird to hear the song with the incorrect note(s).
- The Beat - A character (either the gorilla, goat, or hippo) will play a rhythm pattern. The beats will appear on a banner above the character. You must repeat the pattern by tapping on the space bar key. You need to have the correct number of beats and the correct timing. If you click on the character, they'll play the rhythm again. Complete three patterns to find a sour note.
- Melody Maker - Melody will play a short tune with her Musical Pigs or Hornbirds. Each animal sings one of the musical notes on the music scale. You need to repeat Melody's tune by clicking on the animals in the correct order.
- Melody's Bridge - You can make free form music here. Click each string on the bridge to make a sound. You can also hold the mouse button and drag the mouse over the strings to play them. You can use the gramophone to record your own tunes.
- Instruments Have Lost Their Sounds - The musical instruments have all lost their voices. The Minor Birds can restore their voices, but you must select the correct one. A flock of Minor Birds will appear beneath an instrument that has lost its voice. Each bird can mimic one instrument's sound. Find the bird whose sound matches that of the instrument.
- Jam with Cool Cat - Play Cool Cat's drum set with the keyboard. The left side of the keyboard plays the left hand snare drum. The right side of the keyboard plays the right hand snare drum. The space bar plays the bass drum, and return/enter plays the cymbals. You can use the gramophone to record your own tunes.
- Bagging the Sour Notes - Sour Notes will dart around the screen. Click and hold the mouse button to grab a sour note. Then drag it into Hopsalot's bag.