Board Thread:Questions and Answers/@comment-25094659-20160720152252/@comment-27701762-20160724231556

Kkanekii wrote: I'm in the exact same situation...I'm not sure whether I should just keep on sparing Asgore (that is progressing the game somewhat), or whether I need to reset and begin again. It doesn't seem like an actual ending to just be dumped back in the game. From this I get that after Flowey tells me to "prove his philosophy wrong" ( " I've been thinking. Is killing things really necessary? ... Prove to me you are strong enough to survive. Get here from the beginning. Without killing a single thing... ...and I won't kill the king. ...and, maybe... Then you'll have your so-called 'happy ending.'") I just need to reset and do a pacifist run. Is that right? Yep. Killing anything throughout your playthrough (with two exceptions) takes you off of doing a True Pacifist playthrough.

The silver lining, though, is that you will get an opportunity to go back through the game and experience the little changes that occur with a reset.