https://hiddenpalace.org/Super_Ninja_Boy_(prototype)

Localization prototype of Super Ninja Boy, has a lot of remants of the Japanese game, plus some stuff not found in either retail version (including a map test mode and some early stage layouts).

More info here:

https://tcrf.net/Proto:Super_Ninja_Boy

Really really cool stuff. I love Super Ninja Boy, so seeing a bunch of stuff pre-revision is awesome, thanks for sharing!

What are the chances that you hold onto this game after documentation?  

Little Ninja Brothers was my favorite NES game, one day I have to play through the rest of the series!

Now's as good a time to start as any! I actually haven't played any other games in the series, but I'm really liking SNB so far.
 

Awesome! I need to play through this as well sometime.