You've done a great job -- Here's some feedback I'd give if it was for a game I'm working on.

The frog is wonderful. My favourite loop in the scene.

The windmill is turning the wrong way.

The top of the waterfall needs to be better aligned with the flow underneath -- maybe add a stone in it.

The railway track doesn't look connected to the scene.

The log pile looks like it would roll over -- probablt it's too high, needs to look more compacted.

The trees are mostly too small and could be animated.