Hi All, from what I can tell you need to install DosBox emulator in order to run old school Dos games. This can be done by running the following command:
sudo apt-get install dosbox
You will need to run through the setup process to ensure Dosbox is configured properly before you are able to play any games on it. For a full guide please see this link:
http://www.codingepiphany.com/2013/03/30/raspberry-pi-retro-gaming-mania-part-2-dosbox/
Hope this helps :)