That grey bit at the top is the Famicom-to-NES adapter (the games are the same, but NES games have more copper contact pins than Famicom games, basically)

It has a headphone jack on the bottom

It also has (two) controller ports so you can play two player games. But here's the fun part -- the controller ports are standard DB9 serial ports, which means you use a Sega Genesis controller instead of an NES controller!

Another interesting thing is that it does have audio/video out so you can hook it up to a TV and sue it like a regular console -- but it uses the Sega Genesis video out connector! OK!

It still works. The AC adapter power doesn't but using 6 AA batteries does. Yes, the cartridges go in backwards, something that made me waste 5 minutes and a lot of cuss words.

Here's me playing an unlicensed game (Dizzy) plugged into an unlicensed accessory (Aladdin Deck Enhancer), plugged into a handmade Famicom-NES adapter, plugged into an absolutely hacked together unlicensed portable Nintendo.

OK, I think that's all the video game (mostly Nintendo) oddities I have lying around. If I find anything else during my cleaning of closets during a pandemic, I'll add to this thread.