Hacknet was a great – and surprisingly popular – hacking sim which not only simulated the process of hacking, but did so using real methods, such as the deployment of UNIX commands. Since then the game has received a major campaign update in the form of Labyrinths, but its latest addition includes the ability to make your own campaign narratives.
Dubbed Hacknet Extensions, the update lets players "create their very own Hacknet campaigns, system networks, nodes, themes, music and story missions". These can be uploaded and shared through the Steam Workshop, or simply enjoyed at home. Who doesn't want to create their own hairy, paranoid hacking expeditions?
It seems like a pretty exhaustive toolset: they include features not used in the vanilla Hacknet game, and there's an interactive tutorial to get you on your feet (or fingers, I guess). To celebrate, the base game is currently heavily discounted on the Steam to the tune of 66 percent, and there's also a "friendly mod" competition ongoing called #HackerJAM, with nice rewards going to the best Hacknet mods. More details on that over here.