What (Windows, Mac, Steam Deck) are you using?
When you search for a "free ROM download," you are likely looking for a file that can be played on an emulator (like Kega Fusion or RetroArch). While these files exist, downloading copyrighted ROMs that you do not own is illegal in most regions.
According to SteamDB, the application has been officially "retired" and cannot be purchased. While the Steam page for the game still exists as a placeholder, the "Add to Cart" button is gone. This is not a technical glitch; it is a result of a complicated legal and licensing dispute, primarily concerning the game's iconic soundtrack.