Board Thread:General Discussion/@comment-26347196-20160410032827/@comment-29072186-20160715144304

I definately found the Grand Dunk to be harder than Undyne while doing a normal run, but on the other hand, while I was doing a no-heal genocide run, I was stuck at Undyne for quite a while, taking up at least 3 hours of my time. She was a tough nut for me to crack without healing. Sans, however, wasn't as hard. I got to his last attack on my first try but died, and he probably took me about an hour to beat.

If one were to do a no-hit run, I definately think Undyne would be far, far harder to beat than Sans.

Basicly, from my experience:

Sans = Hardest at first

Undyne = Hardest during challenges