Space to continue. This was a complete accident and I turned on hard mode. Well, Luckily for me, I have beaten this guy more times than I care to count. So, I did it first try, it was probably all muscle memory. The things that change are the heart, so you can see what color it is, and the blue bone attacks, ALL OF THEM are now white. It was something to do with my browser that activated it so uhh why not?
https://jcw87.github.io/c2-sans-fight/
