Castlevania is a game released for the Nintendo Entertainment System (or NES) in 1986 in Japan by Konami (1987 in America) and, around 2018, a year after its 30th anniversary, the Romhacking.net community, which produces hacks and translations of old games, decided to celebrate this anniversary by producing a kind of mod that completely modifies its look.
The Mod brings excellent graphics in a 16-bit style, even reminding us a little of the PSX's Castlevania Chronicles Arranged look, which is an official remake of Castlevania released for the X68000 computer. This Mod is used specifically for the Mesen emulator, which allows the use of HD textures for NES games. The modification, unfortunately only affects the look of the game, but some say that it can add tracks and sound effects in OGG too, further improving the way of playing an NES game (and SNES too; Mesen has its own emulator for SNES that allows you to do the same things).
Check out the gameplay of this Mod on this link here and, if you are interested in revisiting Dracula's Castle, just click on this link below, from the Castlevania Modding forum, where there is a download link: