Sevcon uses this 'mini-boss' that appears in the entirety of the level. It's not bad enough for B-rank or C-rank, but not good enough for S-rank. It's annoying to S-rank, but it's not that hard to complete the level. The gameplay isn't that good because of this one flaw.
I love endings where everything just covers the arena and spins around, like Crystal Tokyo. The level looks sick with all the obstacles and the water covering the arena. The Art of War is very appealing in my opinion. Since it isn't appealing and doesn't play the best, it gets an A-rank for me.
There's also the second phase of the drop that has a really bad transition, but there is a big variation between Hardcore and Normal, which is what I want. New Game isn't anything special after you complete the story.