Board Thread:General Discussion/@comment-26347196-20160410032827/@comment-5956954-20160413014230

Richard2005 wrote: The big-boned dunker is way worser.

You can easily remember Undyne's attack after a few tries.

Meanwhile, you can't do it with Sans(unless if you don't heal)

Tbh, Sans would be easier than the Dummy in the Ruins if it isn't because of Karmic Retribution. IME, attacks are more devastating because the damage is instant, and since you are at a low level, getting hit for only 40 milliseconds from Sans's attacks will equal the same damage as Undyne according to the health bar, and karmic retribution is helpful since it acts as hitpoints. This means that if you were at low health, and Undyne and Sans attacked you, and you got hit for that period, Undyne would kill you first. If you are experienced at fighting Sans, you would rather avoid all the attacks entirely, and if you do get hit, it is usually under 20 milliseconds from grazing wrong.

Sans and Undyne's attacks are both hard to remember. They just come with different required styles. Undyne with the arrows and general bullet hell, and sans with some platforming, so that depends on the gamer.