The assets used for the bottom screen are currently included as a binary format, those will be eventually available as .png converted during compilation. These are very easy to change to your liking. Overlays could indeed be an option, i haven't looked into those at all. Overlay support is currently not implemented, if i recall correctly. So that should be fixed first, i guess.
Fast-forward and rewind are good options to have available. Although i've never actually used it myself, but i can see it being useful for some older consoles.
To me, mapping save / load states to the c-stick or any other controller button doesn't seem practical. Not every core i use has the same controller layout, which requires those options to be mapped to different buttons on different cores.
While the bottom screen is basically unused, and available for each core.
My main reason to look into this is dosbox. I'm always a button short. But, i've ran into other cores which may benefit by having a keyboard or numeric pad available. And i can definitely see the first Touhou games requiring a keyboard.
Dosbox-pure should make loading games easier, but i still want to enter my name when i reach a new highscore.
Automatic game detection and button mapping is nice, but you'll still be limited to your controller buttons. A keyboard offers way more buttons, and a touchpad plays way better than emulated mouse using circle-pad.
Otherwise, if your into commodore and amiga. Keep using badda's emulators, they are awesome. Retroarch will probably never outperform those. But i do like having multiple options available.
An other reason to work on this is practice, without any other development experience, retroarch is kind of familiar territory by now. As you may have noticed, none of my ports have the bottom screen utilized. For me, this is the next step in my learning process. DevilutionX with dual screen support would be the goal.
