First of all, when Squidward goes out to tell Squilliam he lied, the Krusty Krab is still see throughable, even through the corner on the left side. When Squilliam goes in, wallpaper is covering the whole room. Yes I know near the end the wallpaper rips but you could see THROUGH both glass walls near the left corner.

Right at the end there is also wallpaper, but when the camera zooms out, all the interior is gone and it looks like the exact same Krusty Krab with the wallpaper gone and everything. It makes no sense. They should have easilycaught that.