https://www.youtube.com/watch?v=K-TRDYYYw5g
A top 10 list of the hardest games I've beaten. Lots of NES/Famicom/FDS games on it.
Ofc this being the FC board you guys are much better at this than me, but still, me being me this is all I could manage so to speak.
Oh, and feel free to write about the hardest games you've beaten too, or the challenges you've done (like swordless Zelda etc, that kind of stuff)