Level detective work needed.

[Lessinath]

So, I found a partially completed level in my list of levels that was all alone I figured, being partially complete, it must be mine.

And then I remembered seeing it somewhere else, but this was after I had saved it a few times.

I am reasonably confidant this is not mine, pre changes. So, can we figure out if that's the case and if so, whose level it was?

Does anyone remember seeing a level like this, or one that was like this in the beginning anywhere?

I will note the areas before the tank hallway are virtually unchanged, except the fireball slide.