Well, I can definately see the inspiration there, but, um, maybe you'd want to stray more into err, less inspired territory. And also into something that sounds less like "Little Nicky, the game, now availble on PS2, Game Boy, and X Box".
Of course, maybe when you actually write it it will actually be a lot different. Who can say. But from what you've said, it sounds a lot like some things that are about already- Spawn, for instance, or that sort of thing.