How to make portable apps?

How can I make portable apps from games like "call of duty" or "last Chaos"? People have been showing me games like this on thier USB drives and they can be played on any computer without installing... How is this so...?

try making an sfx file of the game's directory with winrar
gold3nwing (author) 8 years ago
They dont know how to do it themselves...
lemonie8 years ago
Have you asked them how? L