What Can You do After Beating the Story

In 2017, the Hacknet team added official mod support to the game in the form of Hacknet Extensions, supported by the Steam Workshop:

Extensions are full new campaigns and stories for Hacknet by modders and creators. They feature new computers, missions, themes, programs and more! This launch opens up Hacknet for everyone to make their own stories with the Hacknet tools.

The workshop already has some amazing Extensions on it - I highly recommend "Hacknet B.R.A.P" by Matrix, and "The Slaughterhouse" by Chris Johnson and Catherine Moore. If you're looking for more Hacknet, here it is.

The tools are also available if you want to make your own Extension! The patch comes with an interactive introduction extension that you can play through.

Besides paid DLC and achievements, playing through modded levels or building your own Hacknet mods is most of the bonus content available.