Like their creator said: Fastdosbox is a fork of dosbox, based on the sources of dosbox SVN. It brings to Raspbian the dynrec x86 emulation. In other words a boost of 250% over the official version.
*Speed of a 386DX @ 25Mhz thanks to dynrec x86 emulation.
*Splendid upscaling using dispmanx.
*Based on the sources Dosbox SVN and Dosbox 0.74.
*Between 200% to 250% the speed of Raspbian dosbox v 0.74.
*Console only, no support for X11.
To make it work once installed, go into the game directory and write dosbox exec where exec is the name of the executable, which is usually a .EXE, .COM or .BAT
The have available for 2.49 euros in the PiStore, which I recommend, or you can download the compiled free version compiled by myself (steps to compile apps was mentioned in another post) from this link.