I'm seeing and walking through walls

Hi @diogoffreire , Please check!

Perhaps your Walls and Character don't have Colliders attached to them respectively.

seeing through a wall is whats called a Backface Culling issue. basically from the angle you are viewing the polygons, the renderer (Unity) doesnt register that you want to see them. when that happens, it also means that there is no physics connected to the object since it (at that angle) doesnt exist. try placing a second wall rotated 180 deg. on the y axis from the original wall.

here is a Question with a very detailed answer that you might consider reading. it explains your issue and why it happens a little more in depth than what i have said.

http://answers.unity3d.com/questions/362692/unity-does-not-render-both-sides-of-a-plane.html