This is a total game graphics hack. EVERYTHING has been given a turtles look. Of course, you fight Shredder at the end in an attempt to save Splinter.
Updated for modern emulator compatibility. Originally sourced from
https://www.zophar.net/hacks/nes/super-mario-bros-1/ninjaturtles.html.
Database match: Super Mario Bros. (World)
Database: No-Intro: Nintendo Entertainment System (v. 20180803-121122)
File SHA-1: EA343F4E445A9050D4B4FBAC2C77D0693B1D0922
File CRC32: 3337EC46
ROM SHA-1: FACEE9C577A5262DBE33AC4930BB0B58C8C037F7
ROM CRC32: D445F698