So you’ve heard about Undertale. Maybe a friend won’t stop talking about it. Maybe you saw a clip online and couldn’t figure out what was going on. Either way — you’re here now.
This guide covers everything. What the game actually is, how long it takes, the three routes, and tips that’ll save you from making mistakes you can’t undo.
No heavy spoilers. Just the stuff you need to know first.
What Kind of Game Is Undertale?
Undertale is an RPG made by one person — Toby Fox — and released in 2015. It looks simple. Retro graphics, old-school style. Don’t let that fool you.
The game is about a human child who falls into an underground world full of monsters. Your job is to find your way home. Simple enough.
Here’s where it gets different.
You Don’t Have to Kill Anyone
Most RPGs expect you to fight. Undertale gives you a choice.
Every enemy you meet can be spared. You can talk to them, flirt with them, ignore them — and eventually show mercy instead of landing the final hit. The combat system is built around this.
Kill everyone, spare everyone, or something in between. The game tracks it all.
Does It Actually Matter?
Yes. More than you think.
Undertale remembers what you do — not just in one run, but across multiple playthroughs. Your choices shape the ending you get. Some things you do can’t be undone, even if you restart.
That’s what makes it different from almost every other game out there.
How Long Is Undertale?
Undertale is short by RPG standards. But “short” depends on how you play it.
Casual Neutral Run — 3 to 5 Hours
Your first playthrough will likely be a Neutral run. You’ll fight some enemies, spare some, stumble through puzzles, and reach an ending. This takes most people 3 to 5 hours.
Don’t rush it. The story hits harder when you take your time.
True Pacifist Run — 6 to 8 Hours
The Pacifist route requires zero kills across the entire game. It also unlocks the true ending — the one Toby Fox actually intended as the “real” conclusion.
Plan for 6 to 8 hours if it’s your first time chasing this. Longer if you get stuck.
Genocide Run — 8 to 15 Hours
The Genocide route means killing every single enemy in every area before moving on. It’s slower, harder, and much darker in tone.
Budget 8 to 15 hours depending on your skill level. Some boss fights in this route are genuinely brutal.
Full Completion — 20+ Hours
Doing all three routes, seeing every secret, and uncovering hidden events? You’re looking at 20+ hours. More if you go deep into the lore.
Most players don’t do this all at once. Undertale is a game people come back to.
The Three Routes Explained
Undertale has three main routes. Which one you end up in depends entirely on your choices.
Here’s a quick breakdown with zero major spoilers.
Pacifist Route — Spare Everyone
Pacifist is exactly what it sounds like. You go through the whole game without killing a single enemy.
This isn’t just about not fighting. The game wants you to actively engage with monsters — befriend them, understand them, resolve conflicts without violence. Some characters even need you to hang out with them outside of battle.
The True Pacifist ending is widely considered the “real” ending of Undertale. Most people recommend doing this route first.
Internal link: See our full Undertale walkthrough for step-by-step help through every area, including the exact steps needed for the True Pacifist ending.
Neutral Route — Mixed Choices
The Neutral route is what happens when you don’t fully commit to either path.
You spare some enemies. You kill others. Maybe you kill a boss but spare regular monsters. The outcome changes based on which major characters you killed or kept alive.
There are actually multiple Neutral endings. They range from bittersweet to fairly dark depending on your choices.
Most first-time players land here without meaning to. And that’s fine.
Genocide Route — Kill Everything
Genocide is the hardest and darkest route in Undertale.
To trigger it, you have to kill every enemy in each area before progressing — not just some, but every single one. The game tells you when an area is fully cleared.
This route changes dialogue, removes certain scenes, and ends very differently from the other two. It also has permanent consequences for future playthroughs that many players don’t expect.
Internal link: Dig into the characters and lore guide to understand why the Genocide route hits as hard as it does.
7 Tips Every Beginner Needs to Know
1. Play Pacifist First
Do the Pacifist route on your first run. It’s the intended experience. Everything else builds on it.
2. Your Choices Actually Stick
Undertale is not a game where you can reload a save and undo everything. Some actions are tracked permanently. Be intentional.
3. Don’t Grind
You don’t need to grind in Undertale. In fact, grinding kills enemies — and killing enemies pushes you toward the Genocide route. If you’re struggling with a boss, the solution is strategy, not levels.
4. Read Everything
Talk to every NPC. Read every sign. Check every item description. Undertale puts a lot of story and humor in the corners most players skip.
5. The ACT Button Is Not Optional
Every enemy has ACT options — specific things you can do to change their mood or resolve the fight without fighting. Figure out what each enemy responds to. It’s part of the game, not a workaround.
6. Save Often — But Understand What Saves Do
Saves in Undertale restore your HP and mark your progress. But they don’t erase choices. If you killed someone, saving doesn’t undo it.
7. The True Ending Requires More Than Just Sparing Enemies
The True Pacifist ending has specific requirements beyond not killing. Some characters need you to actively befriend them during the run. We cover exactly what to do in the Undertale walkthrough guide.
Explore the Full Guide
This hub is your starting point. Every section below goes deeper.
Undertale Full Walkthrough: Ruins to Final Boss → Step-by-step guide through every area. Covers all three routes. Includes boss tips, puzzle solutions, and how to avoid missing the True Pacifist ending.
Undertale Characters Explained: Lore, Story & Secrets → Every major character broken down — their backstory, their role in each route, and the hidden details most players miss. Includes Frisk, Chara, Sans, Gaster, and more.
Frequently Asked Questions
Is Undertale suitable for beginners? Yes. Undertale is one of the best games for people new to RPGs. The combat is simple to learn, the story is easy to follow, and you set the pace. Even younger players can enjoy the Pacifist route without much difficulty.
What’s the best route to start with in Undertale? Start with the Pacifist route. It’s the shortest path to the true ending and gives you the full emotional experience Toby Fox designed the game around. The other routes make more sense after you’ve done Pacifist first.
Can you go back and change your route mid-game? You can change how you’re playing at any point — but some damage is already done. If you’ve killed enemies in an area, that area is partially flagged. A full True Reset is required to completely start fresh. The game explains this once you reach a certain point.
Does Undertale have difficulty settings? Undertale has one hidden mode called Hard Mode, but it’s not a standard difficulty toggle. The base game adjusts naturally to how you play. Pacifist is generally easier. Genocide has some of the hardest boss fights in indie gaming.
How many endings does Undertale have? Undertale has three main route endings — Pacifist, Genocide, and multiple Neutral variants. The Neutral ending alone changes based on which major characters you killed. In total, there are well over a dozen different ending variations. See the full Undertale walkthrough for a breakdown of each one.
Is it okay to look things up while playing Undertale? For your first Pacifist run, try to go in mostly blind — the surprises are part of the experience. But if you’re stuck on a puzzle or unsure about a boss, looking it up won’t ruin anything. That’s what this guide is here for.
