If a game is released with a level editor, and if that editor is even remotely user-friendly, it is inevitable that, sooner or later, someone will bother making their own adventure. This is the case of The Celestial Rise.
Embracing and expanding the story of the original world, Heretic created a fun and challenging story-driven world, and from the first few minutes of playing you can see that he's put some serious effort into it! Cutscenes are awesome and stylistically coherent, and a generous amount of new graphics give the world its own distinctive personality.
Let's hope that this custom world will be the first of many, many others!
Info, screenshots and download link (mediafire) at the Metal Venture community forum