Only the theme really.

In hacknet, when you try to hack a target you'll see it has SSH and FTP services running. You run fake programs like SSHcrack.exe and FTPbounce.exe to exploit those services and the you're in.

In hackmud, when you try to hack a target you'll see it has an "ez_35" lock and a "c001" lock. The ez_35 lock requires an unlock word, something like "open", "unlock", "release" and a digit between 0 and 9. The c001 lock requires a color like "red" "purple" "lime". You need to enter the right inputs within the time limit to hack the target. You can do it manually, but most targets have too many locks with too many options to manually guess all of them in time. You'll need to write your own real life script in JavaScript that can detect locks and automatically guess every option for those locks. If you've ever done programming challenges then you shouldn't have too much difficulty writing these scripts. If you're new to programming it's not the easiest tutorial. The game provides very little direct help.