Game does not build whatsoever? Running on Linux Mint

Hello,

I have tried to run the game by first running ./install_32bit_sdl.sh but it keeps giving me an error:

Username for 'https://github.com': ***********
Password for ***********
remote: Repository not found.
fatal: repository 'https://github.com/Doom64/fluidsynth-lite.git/' not found

I have sourced this repo and it doesn't seem to exist, which I was able to bypass by finding a mirror of the deleted repo. I was then able to build but it has a few errors in the c code. Anyone know why this is extremely hard to build?

I then try to run the systemshock executable but it just doesn't work, giving me another error:

./systemshock: error while loading shared libraries: libSDL2_mixer-2.0.so.0: cannot open shared object file: No such file or directory

What's going on here?