Not only would it be hard to implement, I wonder how much such an effect would be an impact on the performance. If you had this kind of graphics as base, it would probably work, but applying a filter or effect afterwards will probably greatly impact on the performance, making the gameplay slow as every frame must undergo the effect, which by itself could cause for unwanted side effects, like not being able to clearly see what areas you can pass through and which are blocking you (background can become indistinguishable from the foreground at places where you need to see where exactly you can go and can't.)