The oldest system I have would be the NES. My brother received it sometime before I was born. I’m just holding onto it for him, though - it doesn’t get played right now. I actually intend to clean it all up and retrobright it before sending it back to him… eventually… The oldest system I have that still gets occasional use would be my Gameboy Color, which I received, with Pokemon Red, for Christmas when I was 8 or 9. Unfortunately, I need to find a better plastic polish, to take some light scratches out of the lens, and until I do, it will remain disassembled… I’ve also been contemplating using the board for a complete boxypixel overhaul, but there’s something about still having my full original GBC that I’m having a problem getting over…

Progress! Yeah, I think I scrubbed at the game boy for about a half an hour before I could get a reliable connection. My guess is that the handshake still isn’t quite completing correctly, and maybe more scrubbing would work? It would be really helpful if you had a known-working cartridge with which to test. Beyond that, though, I would have to do subs Google sleuthing to find anything else.

I will say, though, that your screen seems fine, so it’s probably not that.

Something similar happened with the one I repaired for my mother-in-law. I had to scrub the cartridge loader contacts in the game boy pretty vigorously with a toothbrush and 99% isopropyl alcohol before it would reliably load appropriately. I would suggest doing the same scrub in the cartridge, as well.

IIRC, Game Boy games do a handshake with the system before anything can load, and that is shown on the screen. When the handshake is successful, you get the normal Nintendo logo. When something in the handshake is wrong, you get the corrupted logo screen.

If that gets you past the logo screen, but you’re still having lines on the screen, that’s probably a bad ribbon cable connection. You can reheat the connection points to get a proper connection again, but it’s definitely an exercise in patience. There are a bunch of guides on this one on the Internet.

Yes, and that’s their goal. They don’t want viable universities for the masses.

I haven’t played most of these, but I will gladly add an endorsement to the early Harry Potter games. They often only tangentially related to the movies, but they had some awesome mechanics, and played into the full story really well.