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 walkthrough takes you from your first session to endgame content. Each phase has specific goals, priorities, and milestones. New to the game? Start with our beginner's guide first.
Quick Progression Summary
| Phase | Area | Focus | Build | Duration |
|---|---|---|---|---|
| 1. Start | The Ruins | Bullet dodging in the SOUL box basics | True Pacifist Route | 1-2 hours |
| 2. Early | Snowdin | FIGHT, ACT, ITEM and MERCY mastery | True Pacifist Route | 3-5 hours |
| 3. Mid | Waterfall | LOVE, EXP and LV + gear | Neutral Route or True Pacifist Route | 5-10 hours |
| 4. Late | Hotland | Build optimization | Neutral Route | 5-10 hours |
| 5. Endgame | The CORE | Min-max | Neutral Route or No Hit Challenge Run | Ongoing |
See our maps guide for detailed area breakdowns.
Phase 1: Getting Started (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.
Level/Difficulty: Opening 45 to 60 minutes Key Rewards: Stick, Bandage, Toy Knife, Faded Ribbon, Butterscotch Pie, Spider Donut and Spider Cider from the bake sale
What to Do in The Ruins
- Learn 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. Spend your first session getting comfortable with this.
- Pick True Pacifist Route as your starting build. See our builds guide for why.
- 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.
- Acquire your first equipment upgrade: Toy Knife or whatever's available.
- Clear all main content before moving on.
Phase 1 Checklist
- Understand Bullet dodging in the SOUL box fundamentals
- True Pacifist Route selected and functional
- The Ruins main content cleared
- Ready for Snowdin
Phase 2: Early Game (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.
Level/Difficulty: Roughly one to two hours in Key Rewards: Tough Glove, Manly Bandanna, Bisicle, Cinnamon Bunny, an inn, Papyrus as a friend
What to Do in Snowdin
- Work on FIGHT, ACT, ITEM and MERCY. FIGHT uses a timed bar where stopping the cursor dead centre deals maximum damage. This system becomes critical from here on.
- Farm for Toy Knife if you haven't already. It's the key upgrade for this phase.
- 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.
- Complete all objectives before pushing to Waterfall.
- Consider whether Neutral Route might suit your playstyle better than True Pacifist Route.
Phase 2 Checklist
- FIGHT, ACT, ITEM and MERCY integrated into gameplay
- Toy Knife acquired
- Snowdin fully cleared
- Ready for Waterfall
Phase 3: Mid 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.
Level/Difficulty: Roughly two to four hours in Key Rewards: Cloudy Glasses, Torn Notebook, Sea Tea, Ballet Shoes, Old Tutu, Temmie Armor
What to Do in Waterfall
- Master LOVE, EXP and LV. EXP stands for Execution Points and LV stands for LOVE, and both rise only when you kill. This unlocks a new layer of gameplay.
- Start working toward Stick. It's the best equipment and becomes accessible around now.
- 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.
- This area is the main skill check. If you can clear it, you're ready for late game.
- Start investing in Coloured SOUL modes for the tactical depth you'll need going forward.
Phase 3 Checklist
- LOVE, EXP and LV mastered
- Stick acquired or in progress
- Waterfall fully cleared
- Ready for Hotland
Phase 4: Late Game (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.
Level/Difficulty: Roughly four to five hours in Key Rewards: Burnt Pan, Stained Apron, Empty Gun, Cowboy Hat, Glamburger, Legendary Hero
What to Do in Hotland
- Finalize your build. You should be running Neutral Route or True Pacifist Route with optimized gear.
- Stick should be your primary. If you don't have it yet, prioritize getting it.
- 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.
- Route tracking across a whole run optimization starts here. Small improvements compound into massive advantages.
- Farm this area for the resources needed to push into The CORE.
Phase 4 Checklist
- Build fully optimized
- Stick upgraded to max
- Hotland fully cleared
- Ready for The CORE
Phase 5: Endgame (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.
Level/Difficulty: Roughly five to six hours in Key Rewards: The final Mettaton confrontation and the route into New Home
What to Do in The CORE
- The CORE tests everything. Come prepared with your best build and gear.
- 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.
- The endgame loop: run The CORE, optimize gear, push harder content.
- Experiment with No Hit Challenge Run for a fresh take once you've mastered the standard builds.
- This is where Route tracking across a whole run mastery separates good players from great ones. See our tips guide for advanced strategies.
Phase 5 Checklist
- Endgame content on farm
- Best-in-slot gear acquired
- The CORE fully cleared
- Ready for challenge content
Common Progression Mistakes
- 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.
Key Tips for Smooth Progression
- 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.
For more advanced strategies, see our tips & tricks guide.
More Undertale Guides
- Undertale Undertale Overview
- Undertale Best Builds
- Undertale Tier List
- 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
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