This took many hours finally got a deathless run of this YEP star.
This is the final level of the romhack SMG2: Cosmos Collapse. Music in this stage is My Innermost Apocalypse from The Binding of Isaac.
For any other questions about the game design, level design, etc., please feel free to check out the trailer at    • Super Mario Galaxy 2: Cosmos Collapse...   and ask the creator!