SPOILERS AHEAD
So despite it’s popularity, I’ve never played with Undertale, and it really is an entreating game.
spoiler
After I’ve realized that killing Papyrus did have some major consequences, I decided to spare 0 mercy on the king wishing to go for the asshole route, and after “defeating” Flowey and sparing the king on a reload, I was greeted by a punishment by said flower.
I did a save reset to make a more pacifist run (do I get any difference if I kill zero enemies, or is that too hard of a challenge?), but contrary to the first run, I didn’t encounter with Flowey after falling into the Ruins. Does this mean that my save is still corrupted by Flowey?
Finish your mixed run and play again. Do better next time.
To elaborate, and because the game doesn’t really explain this - there are three “types” of endings.
Obviously, spoilers.
Pacifist, where you do not kill a single enemy(yes, that includes chumps),
Genocide, where you kill literally every single enemy, including grinding encounters in every area until “nobody showed up” or whatever it says(this is meant to be an unenjoyable experience outside of two mildly interesting unique fights, and boy does it succeed)
And “mixed”, which is anything between the two.