Mednafen is a command-line-driven multi-system emulator utilizing
OpenGL and SDL. Mednafen has the ability to remap hotkey functions
and virtual system inputs to a keyboard, a joystick, or both
simultaneously. Save states are supported, as is real-time game
rewinding. Screen snapshots may be taken, in the PNG file format, at
the press of a button. Mednafen can record audiovisual movies in the
QuickTime file format, with several different lossless codecs
supported.

Nintendo: NES, FDS, Game Boy (Color|Advance), Super Nintendo, Virtual Boy.
Sega: Master System, Game Gear, Genesis/MegaDrive, Saturn.
Nec: TurboGrafx-16/PC Engine (CD), SuperGrafx, PC-FX.
Sony: PlayStation.
Apple: II/II+.
Atari: Lynx.
SNK: Neo Geo Poket (Color).
Bandai: Wonderswan (Color).