Unreleased video games tend to show up in ready-to-play forms, but a recent discovery required decidedly more effort. The Video Game History Foundation has reconstructed a lost NES adaptation of the Tom Cruise stock car movie Days of Thunder (one of the blockbuster hits of 1990) using 30-year-old source code floppy disks from the title’s developer, the late Chris Oberth. As Ars Technica notes, this project required more than a little recovery work.

VGHF archivist Rich Whitehouse found one floppy for a “Hot Rod Taxi” project that, when its code was compiled, appeared to just be a proof-of-concept. The real treasure trove was a 21-floppy hard drive backup, but that required running an ancient DOS recovery program that wouldn’t run properly in an emulator — it took a volunteer running a PC from the era to restore “every bit of data” from the backup. Even then, it required a bit of sleuthing to determine how to compile the code, including hunting down a seemingly missing binary file that was key to putting things together.