Portal Walkthrough

Portal throws you into the mysterious Aperture Science facility with nothing but your wits and a revolutionary portal gun. This walkthrough breaks down the most efficient path through GLaDOS's deadly test chambers, helping you master Portal puzzle solutions and advanced techniques that speedrunners use to shave precious seconds off their times.

Whether you're stuck on a particular chamber or want to optimize your playthrough, this guide covers the essential progression milestones and common pitfalls that trap new players. For fundamental mechanics and controls, check out our Portal beginners guide.

Test Chambers 00-02: Learning the Basics {#chambers-00-02}

The opening chambers teach you fundamental movement and observation skills. Chamber 00 is pure tutorial - walk through the door, grab the cube, place it on the button. Simple stuff, but pay attention to the precise placement mechanics you'll need later.

Chamber 01 introduces your first portal gun functionality. The device only shoots blue portals initially, with orange portals pre-placed by the facility. Walk through the blue portal, grab the cube, and complete the circuit. The key lesson here: portals maintain your momentum and facing direction.

Chamber 02 adds the first real puzzle element. You'll need to portal through the observation room to reach the exit button. This chamber teaches you to look for alternate routes and think three-dimensionally about space.

Pro tip: These early chambers take 30-45 seconds each when played efficiently. Don't rush - building good habits here saves time later.

Test Chambers 03-07: Portal Fundamentals {#chambers-03-07}

Chamber 03 gives you the dual portal gun - now you control both orange and blue portals. The solution involves creating a portal bridge across the toxic waste pit. Master the portal replacement timing here, as you'll use this technique constantly.

Chambers 04-05 introduce weighted buttons and timing puzzles. In Chamber 04, you'll carry cubes through portals while maintaining button pressure. Chamber 05 adds the wrinkle of unreachable cube storage areas that require portal solutions.

Chamber 06 presents your first real momentum puzzle. You need to drop through portals to build speed, then redirect that momentum to reach high platforms. This portal flinging technique becomes essential for advanced play.

Chamber 07 combines everything: multiple cubes, portal momentum, and precise timing. The efficient solution involves stacking cubes through portals and using the glass-breaking mechanic to your advantage.

Expected completion time for this section: 8-12 minutes for new players, 3-4 minutes for experienced ones.

Test Chambers 08-11: Advanced Movement {#chambers-08-11}

These chambers introduce deadly hazards and require precise Portal walkthrough execution. Chamber 08 features your first encounter with the deadly energy pellet system. The key insight: energy pellets travel through portals and can be redirected to power doors and platforms.

Chamber 09 demands perfect portal placement under pressure. Turrets force you to move quickly while solving pellet redirection puzzles. Place portals on walls near turret blind spots, and remember that turrets can't see through portals.

The Chamber 10 acid pit requires a specific portal flinging technique. Create portals on the ceiling and floor, drop through to build momentum, then redirect horizontally to clear the pit. This chamber stops many players cold - practice the timing in earlier chambers if needed.

Chamber 11 introduces the deadly moving platform. You must portal across while the platform travels, requiring prediction of future platform positions. The speedrun technique involves portal placement during platform movement for optimal timing.

Test Chambers 12-16: Complex Puzzles {#chambers-12-16}

This section represents Portal's difficulty peak. Chamber 12 requires multi-step energy pellet routing through several portal pairs. Map out the entire pellet path before placing your first portal.

Chambers 13-14 feature complex cube manipulation with multiple switches and timed sequences. The critical insight: you can portal cubes onto buttons from any angle, including dropping them from above through ceiling portals.

Chamber 15 presents the infamous "impossible" room that requires thinking outside the chamber boundaries. Look for portal surfaces beyond the obvious test area - the solution involves portaling into previously inaccessible areas.

Chamber 16 combines every learned technique: momentum building, precise timing, cube manipulation, and spatial reasoning. The chamber has multiple valid solutions, but the fastest involves a specific portal sequence that minimizes backtracking.

For detailed solutions and alternative approaches, our Portal tips guide covers these challenging chambers extensively.

Test Chambers 17-19: Endgame Challenges {#chambers-17-19}

The final test chambers push your skills to the limit. Chamber 17 features the most complex energy pellet puzzle in the game, requiring redirection through four separate portal pairs. Plan the entire sequence mentally before executing.

Chamber 18 throws multiple turrets, moving platforms, and toxic waste at you simultaneously. The efficient solution involves clearing turrets first using portal redirection, then solving the platform sequence without time pressure.

Chamber 19 serves as the final exam, combining every Portal puzzle solution technique you've learned. The chamber requires perfect execution of momentum conservation, precise cube placement, and complex portal sequencing. Most players spend 10-15 minutes here on first attempt.

GLaDOS Boss Fight {#glados-fight}

The GLaDOS encounter isn't a traditional boss fight - it's a puzzle under extreme pressure. You must detach GLaDOS's personality cores while avoiding her rocket attacks and deadly neurotoxin.

Core Detachment Strategy:

Portal to the rocket launcher area when GLaDOS fires
Redirect rockets back at her using portal placement
Grab each detached core and incinerate it immediately
Repeat for all four cores

The fight typically takes 5-8 minutes for new players. Advanced players can complete it in under 3 minutes using optimal portal placement and movement patterns.

Common Mistakes and How to Avoid Them {#common-mistakes}

Portal Placement Precision: New players often place portals carelessly, leading to awkward angles and momentum loss. Always consider your exit trajectory before placing the entry portal.

Overthinking Simple Solutions: Many puzzles have elegant, simple solutions that players miss while searching for complex approaches. Try the obvious solution first.

Ignoring Audio Cues: GLaDOS and the facility provide crucial hints through dialogue and sound effects. Listen carefully for guidance on puzzle mechanics.

Poor Momentum Management: Successful portal flinging requires understanding physics. Higher drops create more speed, and shallow portal angles preserve horizontal momentum better than steep ones.

Advanced Speedrun Techniques {#speedrun-techniques}

This Portal speedrun guide section covers techniques that cut significant time off completion runs:

Portal Peeking: Rapidly placing and removing portals to scout areas without full commitment. Essential for complex chambers with multiple solution paths.

Accelerated Back Hopping: A movement technique that builds speed through precise timing of backwards jumps combined with portal transitions.

Save Glitching: Advanced runners use specific save/load sequences to skip certain puzzle elements. Note that this technique requires extensive practice and isn't recommended for casual play.

Cube Conservation: Efficient cube management involves planning multi-chamber cube usage to minimize backtracking time.

Master these techniques gradually. Start with portal peeking and momentum conservation before attempting advanced movement exploits.

Next Steps: Practice chambers 06 and 10 repeatedly to nail momentum-based portal flinging. These skills transfer directly to advanced chambers and speedrun strategies. Once comfortable, challenge yourself with our Portal tips guide for expert-level techniques and alternative solutions.