Good idea to bring in some fortifications. You may want to model it a bit boxier, though. Keep in mind how these concrete structures are built in real life. Form boards are used to model the shape, and the concrete is cast in this form. In the field and having to rush construction, it is extremely unlikely to see a fortification with a wall that is bent in two dimensions. That is too complex to produce under these circumstances. I'll look for some reference pictures of bunkers on the eastern front and post them later.