Okay, so I wanted to figure out what the saddest ending in Undertale really was. You hear a lot online, right? People talking about feelings and all that jazz from this game. I’d already played through it once, got that nice ending everyone seems to love, the True Pacifist one. Felt pretty good about that.

But then, you know how it is. Curiosity gets you. You see hints, whispers about… other ways things can go. Much darker ways. I wasn’t looking for spoilers exactly, just wanted to understand the range this game supposedly had. Folks online kept mentioning one route in hushed tones, the one they called “Genocide”. The name alone tells you it’s not gonna be fun times and tea parties.
Diving In (Maybe a Bad Idea?)
So, I decided to check it out myself. Booted up the game again, fresh start. This time, the goal was different. Instead of talking, instead of sparing… I had to do the opposite. Everywhere. The game tells you pretty early on how to do it, tracking the kills needed in each area. It felt weird right from the start.
- The music changes. It gets creepy, slow, or sometimes just… silent.
- Characters you might have liked? Gone. Or they react with pure fear.
- The world just feels emptier and emptier.
Honestly, grinding out those kills in the Ruins felt bad. Like, genuinely unpleasant. Toriel’s section? Rough. But I pushed through. Snowdin? Same deal. Waterfall? Ugh. The game actively fights you on this. It doesn’t want you to do it. Some fights get incredibly hard, way harder than anything in the pacifist run. That Undyne fight? Took me ages. Felt less like a game challenge and more like punishment.
The Point of No Return
The whole vibe is just… bleak. There’s no witty banter, no charming puzzles really. Just you, walking through empty towns, the dust of monsters you defeated supposedly gathering on you. It’s grim. The game really makes you feel the weight of it. And then there’s the Sans fight. Everyone talks about the Sans fight. It’s brutal. But the dialogue, the context… that’s what really makes it hit hard. He knows what you did. The game knows.
When I finally got past him (and man, that took forever, seriously thought about quitting), the ending itself… well. It’s certainly an ending. It’s stark. It’s final in a really unsettling way. No celebrations, no group photos. Just… emptiness. And a lingering feeling that you messed something up permanently.

Some people talk about the stuff that happens after that ending, if you try and play again. I saw that too. That, for me, sealed the deal. The game remembers. It doesn’t let you just take it back.
So, Was It the Saddest?
For me? Yeah. Easily. It wasn’t just the final screen. It was the whole process. Turning a world full of characters and personality into… nothing. And doing it deliberately, step by step. It’s designed to make you feel awful, and honestly, it works. It’s effective storytelling, using the game mechanics themselves to make the point.
Playing through it felt like a chore, a grim task I’d assigned myself just to see it through. Not “fun” in the traditional sense at all. It’s sad because you, the player, are the source of all the sadness in that run. You drain the hope out of the world yourself. That’s what stuck with me. Definitely not an experience I’m keen to repeat anytime soon.