Chimera

You have to tackle this with pure physicality, but it's not easy with level 13 physicality. It's fine to come back and clear it after playing 14-15s. It's a very effective song for starting sensor play practice.

979 UG

There are no twists, but there are two 210 12-beat runs... However, since you need some experience from level 14 to clear these runs, I think it would have been more appropriate to raise the level by one more.

I remember evaluating the momentary difficulty of that section as level 15 even during XX.

It's not like there's no trick to getting through those high-speed runs, and you have to move your feet as fast as possible, but the moment you twist, it's a death sentence. So while the difficulty to lock it in is low, it'll take some time until you actually clear it unless you're pretty confident in your runs.