Youtuber Jweii has released a preview of a homebrew version of Castlevania that is intended as a demake for the Atari 2600.
According to Jweii, this small section was made in four to five hours over the course of two days and is the latest in a series of demakes they are making.
https://www.youtube.com/watch?v=X44Za1TZFpo
You can find Jweii’s channel here