Homebrew developer Jweii, who is known for making demakes of modern games, has released a gameplay video demo of an NES demake of Castlevania Symphony of the Night that they made.

The demo was made in 26.35 hours in the span of 9 days.

 

Jweii has also made an Atari 2600 style demake of the original Castlevania

 

See the demo below

 

https://www.youtube.com/watch?v=fCmYW4M1A40&t=60s