Really gorgeous work here. The cutscenes, backgrounds and maps are all stunning, consistent, and very intentional. The music is captivating. All of it serves the story which is spare, thoughtful, and bittersweet. It's largely a "walking simulator” and is, I think, a really good example of the immersive narrative capabilities of that form when it's done well.
I haven't played The Year After yet so I don't know if the story is related, but ERF stands on its own. It takes place in a vision of the future that is vivid and detailed without being overburdened with exposition. The player always has just enough information to understand the emotional weight of what's happening.
The ROM I played (on a physical GBC) didn't seem to have save capabilities, or anything mapped to the Select and Start buttons, but fortunately I played this at a rare moment where I could take my time with the story and still finish it uninterrupted. I recommend playing the whole thing in one sitting. And don't rush through dialogue—this game communicates a lot with very little text!