AWKWARD ZOMBIE

And everyone lived happily ever after.
Until I reset for realz and destroy everyone.

I was playing Binding of Isaac while listening to Undertale's OST.
Dummy came on.
I found Mom's Knife.

There is no way you missed the incredibly obvious cue at the end
There is no way
CHARA KILLED EVERYONE ANYWAY BECAUSE YOU DID A GENOCIDE RUN BEFORE A PACIFIST RUN HOW DID YOU MISS THIS IT CORRUPTS BOTH ENDINGS YOU SEE IT SPELLED OUT FOR YOU ON THE SCREEN

I have no idea who chara is.
Everything looked perfectly fine, Asriel exploded into a bajillion hearts, everyone left the underground, watched a sunset, credits roll with goofy scenes of everyone having a good time in the human world.

Chara is the character you name, the huge dick that shows up at the end of a Genocide run and asks for your soul. Once he takes your soul your Pacifist run is fucked. This happens immediately after killing Flowey. It cannot be avoided.

Are you sure you made it to the very end of the credits in the Pacifist run? You should've been given the choice to leave with everyone or stay with Toriel, and there's a scene at the very end of the credits that depends on your choice. If you leave with everyone there will be a picture of all the characters and Frisk. If you stay with Toriel there's a scene where she leaves another slice of pie in your room while you're sleeping. Both of these scenes are corrupted if you sold out your soul from a Genocide run.

No zhat didn't happen to me, the end scene was fine and my soul didn't get taken in the first run either. I killed everyone I had the chance to fight though in my first run, from the first froggit all the way to flowey/super flowey. Sans just told me to fuck off at the end instead of fighting though.

Oh, you didn't kill everyone, then
That's not a Genocide run, that's a neutral run
You should've been more specific
You have to actively seek out every encounter and kill everything in each area for a Genocide run
You didn't even get to see the cool bosses, and the neutral ending is the most unsatisfying ending
And I just ruined the real Genocide ending for you trying to figure out what went wrong

Nah, I figured there was more with character since I checked their coffin before leaving and it said theres leftover mummy wrappings in it so I guess their zombie is walking around or something. And sans shows he's a scary mf if you killed his brother and more subtly if you didn't.

it's really common for first timers to refer to killing all the bosses as a 'genocide' run though

real common

you really should have realised, considering they came back to the thread like "alright that's all finished " with no further commentary

BOY I SURE AM GLAD THAT THE GAME DOESn't lock you out of the true pacifist ending if in the first time of a run you kill omega flowey because I did, since I didn't know shit and hey: i may have played pacifist but none of the other monsters didn't truly have it in them to hound you at every turn, not even Asgore. Like, he waits for you to show up. For all I knew, flowey's existence was to just fuck everything over and not let you have a good time. And most of the other monsters were a lot easier to talk down from fighting you. In pacifist, you make friends with a lot of your former enemies.

I have a lot of conflicting feelings about this piece of shit

Okay, so if I want to really really fuck everything and everyone, I need to kill every boss and every possible random encounter, and probably that yellow kid with the big head too, right?

Another way to be sure you're on the right track is to check the dialogue at each save point. If all it says is "DETERMINATION" then you're good--it also tells you how many monsters you have left to kill in that area.