Looks like an ordinary NES...
But it's not...
The carts are inserted like into a normal unit. It has volume control and the display attributes can be adjusted. I've found the screen on ebay and it fits really well.
I'm still working on it but it's been running perfectly so far. I want to cover the circuit board with a painted aluminium plate and maybe I manage to make some bezel for the screen as well.
Check out the video of it in action: