Did I mess up my Pacifist run? [Spoilers]

[Fru Fru Brigade]

So... I attacked Mettaton a few times, because I guessed getting the ratings above the yellow bar would be important to sparing him in the long run, and it's actually a pretty effective way to boost them. Does just attacking mess anything up, or do I actually have to kill for there to be problems? I already used the mystery key and intuited he's actually the ghost from the house next to Napstablook, so I'm not sure it would even count anyway.

[BaconflavouredCockmuffin]

Attacking doesn't mess it up.
Gaining EXP and LOVE would, which will be explained towards the end.

[Stelliferous]

also note that using your yellow heart bullets to attack him WON'T damage him and is perfectly safe for your run

[Kazumi]

Originally posted by Stelliferous:

also note that using your yellow heart bullets to attack him WON'T damage him and is perfectly safe for your run

And also required to defeat him.

Also, ghosts can die if they're in a corporeal object when killed. See: Dummy in the sewer

[Slime Drips]

I managed to defeat him without shooting him ever, he still lost his arms and legs and was nothing but a burnt out torso when I left but all that happened automatically over time. I wonder if managing the ratings good enough can get you through without any "damage"?

[Kazumi]

Originally posted by Mallow:

I managed to defeat him without shooting him ever, he still lost his arms and legs and was nothing but a burnt out torso when I left but all that happened automatically over time. I wonder if managing the ratings good enough can get you through without any "damage"?

Good to know that he just loses them automatically. It appears you just need to get him to 10k ratings.