Regardless if/of the poor construction, it looks like they used the wrong block in this situation. Doesn't have a set-back as it goes upwards, almost like they used a free-standing wall block and not a retaining wall block. Or used a retaining wall block and made it go strait up.
They may have gotten away with it if they had used a geo-mesh to tie the wall back into the hill (dead-man). That's the reason for the bowing on the 3-6 course of the wall. Even with a better block, your supposed to use a geo-mesh after the 4th course.
Not sure about the partial blocks either. They did try and make sure that the courses were still staggered correctly after the corners, but usually manufactures have a specific method of modifying the block on the corner to keep the stagger, or provide a corner block. But it's hard to tell if that is a provided corner block, or they split the ends of the block on the corner.
Unless this was the manufactures recommendation, but part of me doesn't believe that.