I’ve ported the current Arduboy2 setup to the Nano and an I²C-Display:
This especially makes breadboard setups simple and cheap. I intend to use this at a school to build very small and cheap game devices.
It’s pretty close to the real thing. Video is slightly slower but games like ShadowRunner run nice and smooth out of the box. Both audio outputs are also there and even two of the three LEDs can be dimmed.
Sound delay and screen flickering are artifacts of the video capture. In real life both don’t happen.