Castlvevania demakes are not a new concept, and a recent project by YouTuber Pigsy to bring Castlevania: Symphony of the Night to the Genesis/Mega Drive has inspired more projects. A Castlevania fan going by LDD has begun to convert Castlevania: Symphony of the Night to the original Game Boy. While the game was not a system pusher on the PlayStation, it will be interesting to see how the game will work on the Game Boy.
LDD has posted a few videos to show the work that has gone into the demake, but has also stated that there is a long way to go until the demake is finished. This will not just be a game that is designed to look like a Game Boy game, but the goal is to have it run on actual Game Boy hardware, and in the videos, you can see that tested multiple times.
See the videos below