Slavehack is described as 'Free online hacking web game. Will stay free forever. You will hack online into npc pc's/websites/banks but you will also hack and be hacked by other players ;)'. There are six games similar to Slavehack for a variety of platforms, including Windows, Mac, Linux, Android and iPhone. The best alternative is Uplink: Hacker Elite. It's not free, so if you're looking for a free alternative, you could try HackerForever or Hacker: Cyber Warfare. Other Slavehack like games are Hack Run (Paid), Hacker Evolution Untold (Paid) and Digital: A Love Story (Free).
Uplink is a video game released in 2001 by the British software company Introversion Software. The player assumes the role of a hacker in the year 2010, who begins work for the Uplink Corporation, which is a worldwide company providing work for hackers.
In this game you play a hacker. When you first log in to your hacking console you get an email from someone you don't know, who asks you to do a hack for him because he heard great things about you. If you succeed, your name will become more known.
Hack your way into the heart of a mysterious organization to uncover their secrets. Hack RUN is a game which uses 'old school' command prompts (like UNIX) that simulate a real operating system. Learn the commands of each system to help you navigate through your adventure.