This hack is based on one of the NES Remix's mini games, which the levels 1-1, 6-2 and some parts of 3-1 the graphics turned into shadow.
Now you can play the whole game with shadow graphics, on your NES
Database match: Super Mario Bros. (World)
Database: No-Intro: Nintendo Entertainment System (v. 20210216-231042)
File SHA-1: EA343F4E445A9050D4B4FBAC2C77D0693B1D0922
File CRC32: 3337EC46
ROM SHA-1: FACEE9C577A5262DBE33AC4930BB0B58C8C037F7
ROM CRC32: D445F698