I've somehow turned x-ray on for all objects in my project, or so it seems. No matter which object I put in front of the others I will look right through all the layers of objects until I see the last object in the line.
I still see the objects in front, but when there's an object behind the "front-object", then I look through the front-object and see the objects behind it as if they were in front.
If I'm only looking at a single object (in this case a 3D-object), then I don't see the face I'm looking at, but I see the backside and the sides.
When I use the Blender Render, there's no problem, but when I switch to Blender Game Engine and press play, then I look through everything.
What is the problem?
Here are 4 examples of my problem: