A virtual private network (VPN) links two computers through an underlying local or wide-area network, while adding control information as it passes through the layered model the data and keeping it private.
Regards to gaming - It was created for playing against peers over LAN when the Internet was a thing not many of us were privileged to have.
I remember playing RTS games with my brothers in the mid 90's like Z and Starcraft against each other on different computers.
Now with routers and wireless technology and the Internet being a household item in equal importance to the television you can play online games. Most games do have online capabilities and LAN is no longer being implemented into games. Applications are being made to bring back this feature such as Hamachi, Garena and Tunngle.
Most of the apps are a pain in the ass to set up, especially port forwarding, port triggering or DMZ on the router to allow you to play the games online.
Nowadays these VPN allow those who download illegal copies of games to play them online. However it also has a legitimate purpose for those who are strapped for cash and can not afford paying monthly fees that many companies are implementing to play online.
I personally recommend Tunngle - as it's the easiest to set up and is being updated and supports the latest games.
Tutorials can be found via their website or YouTube.
