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