I noticed that the leaves are still well light even when the sun is directly behind them.
Is that intention to simulate transparency? It looks a little odd when everything else is dark on the backside but not the tree tops.

Is it also normal that the frame count goes way down when I go close to the window or the door when they have shadows on them?
I loose about have...

Apart from that, it's absolutely amazing! This takes the Gamestudio graphics to the next level.

I just tried a forest of 250 palm trees and the performance loss is really not that bad. I'm still at about 40 frames.

My system (notebook):
Intel Core 2 Duo T9400 2,53 Ghz
GeForce 9650M GT (1GB)
4 GB Ram
Windows Vista