How about one of the hardest NES games ever made Ninja Gaiden : r/nostalgia

This is the hardest level of any video game I've ever played. What were they thinking? : r/castlevania

15 Hardest NES Games of All-Time

10 Games that Defined Nintendo Hard - DKOldies: Retro Game Store

Which are the must-play games on the NES system? - Quora

Top 100 NES Games

Collective Review: Ninja Gaiden Trilogy » Old Game Hermit

Ninja Gaiden Review (Wii U eShop / NES)

25 Best NES Games of All Time

10 Hardest NES Games We Still Can't Beat Today

The 20 hardest games for the original NES console

I just beat Ninja Gaiden for the first time! : r/nes

Ninja Gaiden -- NES Nintendo Original Classic Game CLEAN TESTED GUARANTEED 18946110073

Top 10 Nintendo Hard Games According To DK Oldies - The NES Page

The MOST DIFFICULT Retro Game Ever Made? — NINJA GAIDEN (1988)

The 20 hardest games for the original NES console