The error "System.Exception: Magic number is wrong: 542" is a bug with mono + ncurses 6.1 new terminfo file format. Easiest workaround is to launch the game from a terminal with:
$ TERM=xterm ./Hacknet
After that, if you encounter the following error: "./Hacknet.bin.x86_64: error while loading shared libraries: libgconf-2.so.4: cannot open shared object file: No such file or directory" you'll need to either install the deprecated libgconf library or use the steam runtime (if steam is installed on your machine) as follow :
$ $HOME/.steam/steam/ubuntu12_32/steam-runtime/run.sh env TERM=xterm ./Hacknet