Okay, I was watching a marble roll around on the floor a few minutes ago, and a thought struck me: a game based off the rolling of a marble. Okay, here's the deal: you get to push a marble into a region of darkness, trying to get it into a certain goal. The problem is that you don't know the shape and terrain of the dark area, but you can find out based on how the marble rolled in your previous tries. Maybe at the beginning or as an easy level, the terrain is revealed as the marble rolls.
I have a general idea on how to implement it. Open spoiler for programming talk.
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Okay, so rolling the marble will be a simple mouse-drag deal. From there, calculating how the terrain will change its path. There will be hill/depression objects that have locations and some algorithm to decide the shape and slope of its inclines. There will be other objects to calculate the slope of the hills at the location of the marble, and to change its velocity based on the slope.
To render the terrain, I will have two images. One will go underneath and will have terrain mapped on it based on the aforementioned hills. The one on top will be a cover, and when a marble travels over it, it acts like an eraser, changing the pixels' colors from opaque to transparent.
One problem though. It's not quite exciting or addictive enough to make a good game. Any suggestions to improve it?