There is a tool out there called a Sonic 2 MP3 tool. The tool allows you to replace any of the songs in Sonic the Hedgehog 2 with any MP3 from your music library to play in the background. In order to make it possible, all you have to do is to rename the file to the part of the game you want the song to play in. You can learn what the song orders are in the Sonic 2 sound test in the options menu, you can view what song is being played on the tool itself, or you can google the song list.

This is my personal custom soundtrack for sonic the hedgehog 2:

- Dream Chaser (F-Zero X) Emerald Hill Zone
- Brinstar (Super Metroid) Chemical Plant Zone
- Stickerbrush Symphony (DKC 2) Aquatic Zone
- Happy Humming (DQ VI) Casino Night Zone
- Mountain Zone (Ys VI) Hill Top Zone
- Be Careful (Ys III) Mystic Cave Zone
- Devil's Lab (FF VI) Metropolis Zone
- Flight theme 2 (Bahamut Lagoon) Sky Chase Zone
- Launch (FFX) Wing Fortress Zone
- Original Hito Unit Residence (MML) Death Egg Zone
- Still More Fighting (FF VII) Boss theme
- Ultimate Showdown of Ultimate Destiny (Lemon Demon) Final Boss theme
- Superman (Goldfinger) Invincibility
- Through the Fires and Flames (Dragonforce) Super Sonic theme
- Can You Feel the Sunshine? (Sonic R) Special Stage
- Game Over (MML) Game Over theme
- Character Select (Mega Man & Bass) Stage Select theme
- Password theme (MM7) Continue theme
- Victory theme (MMX Command Mission) Stage Clear
- Fanfare 3 (CT) Extra Life
- Staff Roll (MMX3) Ending Credits