Here is the full list of all 11 Hacknet achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Complete the tutorial earlier than normal
Complete Bit's final request
Run Clock.exe
Run ThemeSwitcher
Be granted an account within CSEC
Master of /el's friendly community
That's just impolite
Disconnect from a traced system with less than half a second to spare
Have a truly absurd number of pointclicker points
Purchase the final PointClicker upgrade
Be granted an account within Entropy