I know I've posted this before, but anytime anybody gets excited about something like this, it reminds me of this comic.
Eh, each to their own. I know folks who would give you (and I) a hard time for playing old video games and calling it fun. Keep that in perspective when you give someone else a hard time for liking a particular bit of hardware or software. We're all nerdy/passionate about something that someone else finds stupid.
On topic, I've had a long standing desire to make an "oversized" GameBoy/GBC at one point, just for lolz. The Pi-Zero-W would be perfect. Lightweight enough to run from a "powerbank" style battery and drive a 7" screen. Plan is to make it double the X and Y dimensions (puts it at about the size of a standard A4 piece of paper, similar to any modern tablet, and a screen that's almost exactly as tall as a 7" 16:9 display that I could put a mask over to make it look like a GB screen), keeping the depth the same. I'd love to 3D print the whole thing if possible.
Failing that, the backup plan was a "wall art installation" style setup I could hang on the wall at home that had a Game and Watch simulator running in it.
Any of those tasks should be trivially handled by a Pi-Zero-W, be cool enough to be kept in a tight space with limited airflow, and potentially even battery powered.