Board Thread:Questions and Answers/@comment-31235848-20170605124639/@comment-33036560-20171107143207

A lot of it is muscle memory. I did it with toy knife and torn ribbon (because I refused to use anything else.)

The circle ones are pretty tough, but you need to aim between them. Move up when needed (later in the fight you'll most certainly need to do this) and go left, reach the end of the screen and change direction when they are they are at their widest. I haven't played genocide in a long time (I actually never finished, I spared Sans and gave up Because feels) but I beleive that sea tea will help as well. Try to get the fight finished as quickly as possible to limit her attacks gaining speed and difficulty. ANother thing is try not to get too worked up with her. This is more of a Sans thing, but if you are extremely frustrated you may do poorly. It's okay to be a little angry while doing Undyne because her attacks don't need as much precision, but if you are justed raged take a break, breathe, and get yourself a snack.

Stay determined, you'll get it!