What are the 69 songs in these packs?
For those unfamiliar with Nine Inch Nails.

Most of these were taken from the old nin.remix website (which is no longer available sadly as the site was shut down some years ago)

I don't have a list anymore of what the original songs were, you can blame a younger version of me. But they are instrument sampled so there are no lyrics and not the original release of the songs as they were sampled in the site and reuploaded as "new" remixes I downloaded years ago.

Some are just straight instrumentals of original songs others are true remixes. But they all fit to what I think is a good theme for Factorio.

With that said I always support the music shipped with the game (be nice and buy the soundtrack) but just wanted to add more "heavy" especially for biter death worlds and long rail worlds.

All good.
Thanks for your work on this mod.
I'm enjoying it quite a bit.

07 - La Mer
38 - The Wretched
45 - The Great Below
53 - The March

Here's a few I was able to identify, I'd do the rest but I don't have the time, I did a couple by hand by looking at NiN playlists and paying attention to similar timestamps and comparing them to the lengths of each song. Also audiotag.com can help, though it proves only somewhat effective, some songs are too long, you'd have to cut them to the first 2 minutes and apparently there's a program called braintunes that can scan mp3 files, and scan a datadabe to figure out the metadata for a song and add it but am unsure about ogg files. I guess you could convert them to mp3 files.
If I have some time, I can identify the rest if you guys would like.

I went back and started listening to the original songs from the albums, what a trip, as I had used these instrumental tracks for so long I forgot what the lyrics sounded like.

But what seems to be the case most are sourced from the NiN albums:
The Downward Spiral
The Fragile
With Teeth