What this utility does is run 2 copies of a special version of the emulator gens which I have created, allowing you to load up two roms and compare minute differences. This version of Gens has been modified to have non-foreground access to the keyboard, meaning that you will always be controlling it, regardless of whether the window has focus. In theory you could even run more than 2. Download: http://jmuz.net/dual/dualgens.zip To use... 1. Run the dual.exe program, you can then use the options on the right to select the 2 roms you wish to compare, though you can also do this from within the two copies of gens. 2. then click "Run and Detect Instances". 3. Once they have loaded click "Sync Reset" and play! You are now controlling both emulators at the same time.