The art of a Pass: Complete
Complete is what it sounds like, with some caveats. This is where fixes start happening, anything you had to do to quickly go through the last pass (see kitbashing) gets finalized with proper art, and aspects beyond the golden/critical path gets some love. What parts do you focus on? Well that depends on what your own tests during the Gameplay pass was. Realistically that should mean "all of it", but keep in mind that aspects that are more art driven, like lighting and clutter may not be in that category. At the end of this pass, you should be able to put the current state of your level in front of a player and only feel bad about it, but not cause them to feel the same. The tests from this should help aim you where to begin your next pass: polish.