Undertale is Toby Fox's 2015 role playing game about a child who falls into the Underground and has to find a way out. Its hook is that every encounter can be ended without killing: you dodge patterned attacks inside a small box, then use ACT and MERCY instead of FIGHT. A single run takes roughly six to seven hours, and the game quietly records what you chose to do along the way.
This guide covers everything you need: core mechanics, the best builds, equipment worth investing in, location progression, and the tips that actually make a difference.
Core Mechanics
Bullet dodging in the SOUL box
On an enemy turn your SOUL becomes a small red heart inside a rectangular box and you dodge projectile patterns with the arrow keys. You start on 20 HP, so two or three clean hits from a mid game attack is fatal.
FIGHT, ACT, ITEM and MERCY
FIGHT uses a timed bar where stopping the cursor dead centre deals maximum damage. ACT holds enemy specific options like Check, Flirt or Compliment, and using the right ones turns the enemy's name yellow in the MERCY menu so it can be spared.
LOVE, EXP and LV
EXP stands for Execution Points and LV stands for LOVE, and both rise only when you kill. Staying at LV1 keeps you on 20 HP for the entire game, while LV20 puts you on 99 HP, so it is a difficulty setting as much as a moral one.
Coloured SOUL modes
Several bosses recolour your SOUL and change the rules entirely. Blue drops you to the bottom of the box so you jump, green pins you in place behind a directional shield, yellow lets you shoot back, and purple traps you on horizontal lines.
Route tracking across a whole run
The game counts kills, spares, deaths and dialogue choices, and it holds those counts across saves. Which of the three main endings you reach depends on what those counters say when you get to the end.
For a deeper dive into how these systems interact, see our Undertale combat guide.
Builds Overview
| Build | Tier | Playstyle | Key Stats |
|---|---|---|---|
| Neutral Route | A | Versatile approach | Balanced stats |
| True Pacifist Route | A | Versatile approach | Balanced stats |
| Genocide Route | A | Versatile approach | Balanced stats |
| Hard Mode | A | Versatile approach | Balanced stats |
| No Hit Challenge Run | A | Versatile approach | Balanced stats |
For full build breakdowns with gear and stat priorities, see our Undertale builds guide. For rankings, check the tier list.
Equipment Guide
| Equipment | Why It Matters | Best For |
|---|---|---|
| Stick | The starting weapon at 0 attack, found in the Ruins. | LV1 runs and anyone intending to spare every monster in the game. |
| Toy Knife | 3 attack, found in the Ruins. | Early neutral runs where Froggits and Whimsuns take too many turns to clear. |
| Worn Dagger | 15 attack, found in New Home near the end of the game alongside the Heart Locket. | The final stretch of a neutral run. |
| Burnt Pan | 10 attack, found in Hotland. | Runs built on stacked healing food rather than raw damage output. |
| Real Knife | 99 attack, and it only exists on the Genocide route. | Genocide runs, where it removes almost every encounter in a single hit. |
Stick: The starting weapon at 0 attack, found in the Ruins. It adds no damage at all, which is precisely the point on a pacifist run where you never swing it.
Toy Knife: 3 attack, found in the Ruins. The first real upgrade and the earliest signal that the game will arm you if you decide you want that.
Worn Dagger: 15 attack, found in New Home near the end of the game alongside the Heart Locket. It is the strongest weapon available outside the Genocide route.
Burnt Pan: 10 attack, found in Hotland. Its real value is the passive effect: every consumable item heals 4 more HP while it is equipped.
Real Knife: 99 attack, and it only exists on the Genocide route. Paired with The Locket at 99 defence it is the highest stat spread the game will ever hand you.
Full breakdowns in our Undertale weapons guide.
Location Progression
| Location | Level Range | Key Rewards |
|---|---|---|
| The Ruins | Opening 45 to 60 minutes | Stick, Bandage, Toy Knife, Faded Ribbon, Butterscotch Pie, Spider Donut and Spider Cider from the bake sale |
| Snowdin | Roughly one to two hours in | Tough Glove, Manly Bandanna, Bisicle, Cinnamon Bunny, an inn, Papyrus as a friend |
| Waterfall | Roughly two to four hours in | Cloudy Glasses, Torn Notebook, Sea Tea, Ballet Shoes, Old Tutu, Temmie Armor |
| Hotland | Roughly four to five hours in | Burnt Pan, Stained Apron, Empty Gun, Cowboy Hat, Glamburger, Legendary Hero |
| The CORE | Roughly five to six hours in | The final Mettaton confrontation and the route into New Home |
The Ruins: The opening area, a purple stone maze of switch and rock puzzles under Toriel's care. It teaches ACT through Froggits and Whimsuns, hides the Toy Knife and Faded Ribbon, and closes with the game's first real boss fight.
Snowdin: A snowfield and town run by Papyrus and Sans, with a run of deliberately silly puzzles, a set of dog themed enemies and a shop stocking the Tough Glove and Manly Bandanna. It is the most forgiving stretch of the game.
Waterfall: Dark caverns of glowing crystals and echo flowers, with Undyne hunting you across bridges and reed beds. Gerson's shop sits here, and Temmie Village hides off the main path.
Hotland: Lava, conveyor belts and Alphys's laboratory, plus a string of Mettaton set pieces that use the yellow SOUL shooting mode. Bratty and Catty run a stall outside the MTT Resort.
The CORE: The Underground's power plant, a blue and grey maze whose layout shifts depending on choices you made earlier. It is the last area before New Home and the shortest of the major zones.
See our maps & locations guide for detailed area breakdowns and our walkthrough for the optimal progression path.
Tips That Actually Matter
- Use Check on every new enemy before anything else. The flavour text points at the ACT option that will spare it, and it costs one turn you were going to spend dodging anyway.
- Toriel's phone number is not decoration. Calling her from different rooms produces different lines, and in the Ruins the phone is part of how the area is meant to be played rather than an optional extra.
- Buy at least one Spider Donut or Spider Cider from the bake sale in the Ruins. Muffet in Hotland checks whether you supported the spiders and behaves very differently if you did.
- Temmie Armor lists at 9999G, more gold than a normal run produces. Talk to the Temmie asking for college money and pay repeatedly until the price falls to 1000G, at which point 20 defence carries you through almost anything.
- Sparing is often a sequence, not a single action. Some enemies need several ACT commands in order and some need their partner spared first, which is why the dog family in Snowdin catches new players out.
- Green SOUL mode in the Undyne fight removes your ability to move at all. You hold a directional shield instead, so read the direction each spear comes from and face it rather than trying to dodge sideways.
- Yellow SOUL mode inverts the game during Mettaton encounters and lets you shoot upward. Keep firing between dodges, because both damage and the on screen ratings depend on how much you put out.
- Every save point is also a full heal, and one sits before each major fight. If you walk into a boss on damaged HP, you walked past a save point.
- The True Pacifist ending requires zero kills across the entire run, not just the closing chapters. One accidental kill in the Ruins blocks it until you finish a neutral ending and go back through.
- The Genocide route is a grind rather than a rush. Each area has to be emptied until random encounters stop spawning, and two of its fights are far harder than anything on the other routes.
Common Mistakes to Avoid
- Killing a handful of monsters early and then aiming for True Pacifist. Any kill at all blocks it for that run.
- Spamming FIGHT on Toriel because the ACT options look like they are doing nothing. Sparing her takes many attempts and the game expects persistence.
- Walking past every shop and reaching the endgame with three items and no armour.
- Selling the Butterscotch Pie for gold. It heals 64 HP and has a specific extra effect in one late fight.
- Sampling the Genocide route out of curiosity and assuming a reload undoes it. The game keeps records across saves.
Frequently Asked Questions
How long is Undertale?
A single route runs roughly six to seven hours. Seeing all three main endings, including True Pacifist and Genocide, takes closer to 20 hours in total.
Do I have to kill anything?
No. Every enemy in the game, bosses included, can be resolved through ACT and MERCY. Finishing with zero kills is the requirement for the True Pacifist ending.
What do EXP and LV actually mean?
EXP is Execution Points and LV is LOVE. Both rise only from killing, and both raise HP, attack and defence. LV1 leaves you on 20 HP for the whole game while LV20 puts you on 99.
Which route should I play first?
Neutral, without reading anything first. The game is built around reacting to uninformed choices, and the pacifist ending is designed to be reached after a neutral ending rather than before it.
Is Deltarune a sequel?
No. Deltarune is a separate Toby Fox project that shares characters and art style without continuing Undertale's story. Undertale itself released on 15 September 2015.
More Undertale Guides
- Undertale Best Builds
- Undertale Tier List
- Undertale Walkthrough
- Undertale Beginner's Guide
- Undertale Tips & Tricks
- Undertale Weapons Guide
- Undertale Combat Guide
- Undertale Boss Guide
- Undertale Maps & Locations
- Undertale Crafting Guide
- Undertale Classes & Characters
Similar Games
If you enjoy Undertale, check out these related guides:
- Elden Ring Guide: rpg game with similar mechanics
- Baldur's Gate 3 Guide: rpg game with similar mechanics
- Cyberpunk 2077 Guide: rpg game with similar mechanics
