So here is an update on this sprite sheet to include the secret area located just off to the right of the rest of the level. I'll admit, I've known about this secret area for years now since I read about it on the games TCRF article, but I didn't originally include it because I felt more research had to be done on it. I was skeptical as to whether or not it was actually apart of the main level and if it was even rendering correctly after modifying the rom per the instructions on TCRF. However, through my own research, I was able to get a good look at it without doing this and even figure out where in the level it was.

Now something else I want to stress is the transparent gap between the main level and the secret area is not a mistake or oversight, there is simply nothing there in game, hence why it looks like this.