Thanks for the comments, everybody.
Ashley: Thanks. On the shadow thing, I've been working on it using the method you suggested to some success. I'll work on it some more later and see if I can get it working right.
ssbfalcon: Thanks. I'm mostly just making the engine now to see if I can do it, but I do want to make something later down the road.
TheInstance: I was basically explaining the use of containers for the terrain detectors. The detectors each have a terrain graphic in their container, so instead of placing detectors and terrain pieces, you only have to place the detectors and the terrain pieces will be created automatically. Hope that explains it better.