All the available emulators that run(nes, gbc, snes) are... Bleh. The gameboy one has an insanely tiny screen. Ya retro interface, but let me play fullscreen. Snes one has fullscreen, but insanely small buttons with absolutely no deadzone. Very hard to play on my ipad  gba one didn't run very well |
There's a setting for the screen size. You can have full screen or the retro look. My fingers always block the view on the full screen setting.