Help with seeing through objects?

For some reason when I play the game I can see the branches through the leaves, it is not like this before I play it. How do I fix this?

This may be in part a result of the long standing bug that the BGE has with alpha sorting, but can be alleviated a bit by making sure that every face has the ‘sort’ texface option enabled for it (in the edit context in Blender 2.5 and the object panels in Blender 2.49, only visible in editmode)