Back before The Legend of Zelda: Breath of the Wild came out, Nintendo showed off how its team developed the game’s concept. Included in those materials was a 2D version of the game based on the original The Legend of Zelda, which they used to work out the mechanics. Now, a fan has taken that idea and made an actual game out of it.
Breath of the NES is the current name for the project. Winter Drake, the creator, has the in-progress game available on the itchio indie games platform. It’s free, of course, and still in development. Drake built it in Game Maker Studio, and it has some technological features not in line with the NES.
Drake is very aware of the dangers of making a fan game based on Nintendo IP, but is fully prepared for the eventual DMCA claim. He has his own original title and characters lined up for when that happens. So in the future, it’ll be pretty cool to see this neat project develop into its own thing, assuming Drake keeps up with it.