Indeed it is a front end for common emulators.
You still have to do a moderate amount of tuning since I expect people to have a certain preference on how their games run, but it can play your games "out of the box" with no tweaking either. All you would need to do is set up your controller and make sure that your games are in the right format.
I believe the hacking community is already working on porting retroarch to the PS1 Classic.