runinruder - 291400+ (one credit, game complete)
Let me explain the "+" at the end of my score. 291400 is what I had right before I killed the final boss. After I killed him, the stupid rolling score counter was still adjusting my score when the screen faded into the ending. So I don't know what the exact final number was; I just know it was 291400 plus whatever killing the final boss is worth.
I think it'd be pretty easy to take advantage of the way the game works and get insanely high scores. I just figured I'd post this since I bothered to take the time to play through it all in one sitting.
Haha, interesting thread. I might give it a go if I'm feeling up to it, but that will require some time and patience.