I've made a game library/engine myself way back in the day called the Pascal Sprite Engine. Wonderful name, I know. You can probably still find it out there somewhere. It was for Turbo Pascal 7 and it followed a few basic rules as far as functionality and features went. I kept the entire unit structure like a 'black box' you had a list of functions that did everything for you and you didn't have to dabble indie of it or deal with other complicated libraries or functions to make games with it.

I assume that your goal with Prometheus is about the same?