Advanced Maps and Challenges
Portal's Advanced Maps and Challenge Maps are both built from Test Chambers 13 through 18 and reached from the Bonus Maps menu, unlocking one at a time as you clear each matching chamber. Advanced Maps rework the geometry with fewer portalable surfaces and meaner hazard placement, while Challenge Maps keep the original layouts and score you on Least Portals, Least Steps, and Least Time. Six chambers times three categories gives 18 challenges, and Gold on all of them unlocks Aperture Science.
Portal has two categories of bonus content: Advanced Maps and Challenge Maps. Both are built from Test Chambers 13 through 18, reworked for experienced players. Advanced Maps add harder puzzle layouts. Challenge Maps keep the original layouts but impose performance constraints.
You reach both from the main menu under Bonus Maps. They unlock individually and not all at once: each advanced and challenge chamber becomes available as soon as you have completed the matching Test Chamber in the campaign, so you can start on Chamber 13's bonus maps long before you finish the game. Developer commentary is the one thing that genuinely waits for the credits.
Advanced Maps
Advanced versions of six test chambers. The core puzzles remain the same, but the rooms are redesigned to be tighter, less forgiving, and sometimes disorienting. Portalable surfaces are reduced, hazard placement is meaner, and spare cubes are removed. Every advanced map is solvable with the same techniques you learned in the main game. The difficulty comes from having less room for error.
Chamber 13 Advanced
Key change: The first room has no cube at all, and the button sits much closer to the entrance. In the main room, almost the entire floor is replaced with goo, so the puzzle becomes about staying off the ground instead of routing around obstacles.
Chamber 14 Advanced
Key change: The fling now exists to reach the cube and not to move it. Once you have the cube you simply take it down the stairs to the button. The fling uses two floor portals, one down the staircase and one by the box section. The three platforms in the goo room are gone and several surfaces have been made portal-proof.
The famous Chamber 14 shortcut, flinging straight onto the exit lift, belongs to the normal and challenge version of the chamber, where it is the two-portal Gold solution for Least Portals. It was deliberately removed from the advanced version by making the relevant floor portal-proof. Do not go looking for it here.
Chamber 15 Advanced
Key change: Room one loses most of its portalable surfaces, so you need an infinite-fall fling to build speed. The first pellet puzzle gains an extra Emancipation Grill, the second changes the pellet's ricochet path, and room three has no portalable walls and no staircase. The scaffolding also moves faster, and angled platforms have been added.
Chamber 16 Advanced
Key change: Every turret is enclosed in a metal cage. They can still shoot out, but you cannot pick them up, knock them over, or portal them away, which removes every standard turret answer at once. The cubes are not reduced. The side room still holds plenty of cubes and pushable boxes, and using them for cover is now the point.
Chamber 17 Advanced
Key change: The Weighted Companion Cube is replaced by a sphere, which rolls and will not sit still where you leave it. Both pellet receivers gain glass barriers, and an accuracy fling test is added near the end.
Chamber 18 Advanced
Key change: The pellet launcher is removed entirely, some portal-conductive walls are gone, retrieving the cube requires harder flinging, and platforms lower as you travel through them via a portal. Note that the opening ceiling is not portalable, so any route that starts by shooting upward there will not work.
Advanced Map Achievements
| Achievement | Requirement |
|---|---|
| Cupcake | Beat any two advanced maps. |
| Fruitcake | Beat any four advanced maps. |
| Vanilla Crazy Cake | Beat all six advanced maps. |
Advanced maps do not need to be completed in order. If one map is giving you trouble, move on to a different one. Cupcake and Fruitcake pop as soon as you hit the count, regardless of which maps you chose.
Challenge Maps
The same six chambers (13 through 18) from the base game, but scored. Each chamber tracks three performance metrics, and you earn Bronze, Silver, or Gold medals based on your results.
Challenge Categories
| Category | What It Measures |
|---|---|
| Least Portals | Total number of portals fired to complete the chamber. |
| Least Steps | Total footfalls. Discrete steps, not movement ticks, so standing still is free. |
| Least Time | Total seconds from start to finish. |
Least Steps is unique to the first game. Portal 2 has no equivalent category.
Six chambers times three categories gives 18 challenges in total, and that is what the in-game tracker counts when it reads 18/18. Each of those 18 carries three medal goals, so there are 54 goals overall.
Medal Thresholds
The thresholds live in a game data file, scripts/challenges/challenges.bns inside portal_pak_dir.vpk, and not in the engine itself, so modders can edit them. Here are the exact targets for every chamber and category.
Least Portals:
| Chamber | Bronze | Silver | Gold |
|---|---|---|---|
| 13 | 9 | 5 | 4 |
| 14 | 6 | 4 | 2 |
| 15 | 23 | 21 | 14 |
| 16 | 9 | 4 | 2 |
| 17 | 4 | 3 | 2 |
| 18 | 30 | 25 | 16 |
Least Steps:
| Chamber | Bronze | Silver | Gold |
|---|---|---|---|
| 13 | 30 | 20 | 10 |
| 14 | 55 | 20 | 10 |
| 15 | 75 | 65 | 55 |
| 16 | 70 | 55 | 40 |
| 17 | 215 | 175 | 150 |
| 18 | 150 | 120 | 85 |
Least Time:
| Chamber | Bronze | Silver | Gold |
|---|---|---|---|
| 13 | 0:40 | 0:30 | 0:19 |
| 14 | 0:50 | 0:20 | 0:10 |
| 15 | 1:45 | 1:25 | 0:54 |
| 16 | 1:10 | 1:00 | 0:52 |
| 17 | 2:20 | 1:45 | 1:27 |
| 18 | 2:10 | 2:00 | 1:13 |
Advanced Maps vs. Challenge Maps
A common point of confusion: these are two different things that share the same six chambers.
- Advanced Maps have physically altered geometry. Portalable surfaces are removed, pits are extended, and hazard placement is rearranged. You need to solve a harder version of the puzzle. Completion unlocks the Cupcake/Fruitcake/Vanilla Crazy Cake achievements.
- Challenge Maps keep the original, unmodified chamber geometry from the campaign. The puzzle is identical. Your performance is scored against the medal thresholds above. Completion unlocks the Basic Science/Rocket Science/Aperture Science achievements.
Challenge Difficulty Ranking
From easiest to hardest across the community:
- Least Portals. Study the chamber, plan your portal placements, and execute. Reloading saves does not add portals. Take your time.
- Least Time. Requires fast execution but is forgiving of non-optimal routes. Quick-save aggressively.
- Least Steps. Every footfall counts, so this needs hopping patterns, crouch-jump optimization, and careful positioning.
Do them in that order, not because of difficulty but because the routes stack. The portal-efficient solution usually contains the shortcut that the time and step routes then reuse, so solving Least Portals first does most of the work for the other two.
Accelerated Back Hopping is real in this engine, but no Gold medal requires it. Chamber 14's 0:10 Gold comes from the two-portal fling shortcut and Chamber 18's 1:13 from cube-shield routing. Plain constant jumping is the standard time advice.
Least Steps Strategies
The Least Steps category is where most players hit a wall. Here are the techniques that make Gold medals possible:
- Travel by portal, but land slowly. Dropping through a floor portal covers ground cheaply, though it is not automatically free. A fast landing after a long fall does cost a step. The trick is to cancel the exit portal while you are still airborne so you touch down slowly, and the published Chamber 13 route deliberately routes through a low grating first to bleed speed.
- Hop instead of walking, but know that jumping still costs. A jump is not free. The efficient pattern is to alternate a step and a hop, which covers a long distance for 2 steps. Walking the same ground costs far more. Hopping is step-efficient, not step-free.
- Crouch-jump for distance. Press jump followed immediately by crouch (
Ctrl). This gives you extra reach and genuinely saves steps on long stretches, which is exactly how the Chamber 17 route handles its worst section. - Throw objects instead of carrying them. Throwing a cube toward its button from a distance saves every step the walk would have cost.
- Mind the elevator, but do not overstate it. The standard opener costs 2 steps: place a portal right in front of the elevator, then take one step and a hop. On Chamber 13 that leaves you 8 of the 10-step Gold budget, not 5.
A "step" is a discrete footfall event, not a tick of movement. Standing still while you line up portals or manipulate cubes costs nothing at all, landings only register above a speed threshold, and every mid-move course correction adds one. Getting that definition right is what makes the techniques above work.
Challenge Map Strategies
General tips:
- Quick-save constantly. Press
F6before every risky move. If you waste a portal or take extra steps, reload (F7) and try again. The counters are stored in the save file and rewind with it, so a reload genuinely costs you nothing. Every published Gold route depends on this. - Plan before executing. For Least Portals, walk through the chamber mentally and count the minimum portals needed. Check community solutions if you are stuck on a Gold target.
- Ignore categories you are not targeting. Going for Gold Portals? Do not worry about steps or time. Focus one category at a time per chamber.
Chamber-specific notes:
| Chamber | Easiest Gold | Hardest Gold |
|---|---|---|
| 13 | Least Portals (4 portals is tight but logical) | Least Steps (10 steps, with 2 spent leaving the elevator) |
| 14 | Least Portals (2 portals via the fling shortcut) | Least Steps (10 steps across multiple elevations) |
| 15 | Least Time (double fling is fast when clean) | Least Steps (55 steps with fling landings adding contacts) |
| 16 | Least Time (turrets go down fast with good portals) | Least Steps (40 steps with turret avoidance adding footwork) |
| 17 | Least Time (1:27 if you know the Companion Cube route) | Least Steps (150 steps in the longest chamber) |
| 18 | Least Portals (16 portals is complex but countable) | Least Steps (85 steps across the longest traversal) |
Challenge Map Achievements
| Achievement | Requirement |
|---|---|
| Basic Science | Earn Bronze medals on all Portal challenges (all 18 slots). |
| Rocket Science | Earn Silver medals on all Portal challenges (all 18 slots). |
| Aperture Science | Earn Gold medals on all Portal challenges (all 18 slots). |
Aperture Science (all Gold medals) sits at 2.8% global unlock, tied exactly with Rocket Science and Basic Science because Gold cascades down to the lower tiers. Least Steps Gold on Chambers 13 and 17 pushes most players to their limit. Quick-save every few seconds. Be patient. Community video guides show the exact hopping routes for every chamber if you get stuck.
Commentary Mode
Completing the game also unlocks Commentary Mode. Replay the entire campaign with floating speech bubble icons placed throughout the levels. Walk up to one and press your use key to hear a developer explain why a specific design decision was made.
Commentary mode covers:
- Why specific chambers teach specific mechanics.
- How playtesting shaped the difficulty curve.
- The design philosophy behind GLaDOS's dialogue pacing.
- Technical details about the Source engine portal rendering system.
- How the Companion Cube became a cultural icon despite being a box with a heart on it.
You cannot earn achievements while developer commentary is active. Do not run a commentary playthrough expecting to pick up anything you still need. Some nodes also alter the visuals or briefly take control of your viewpoint, so it is not a purely passive overlay either.
Frequently Asked Questions
What is the difference between Advanced Maps and Challenge Maps in Portal?
Advanced Maps physically alter the chamber geometry by removing portalable surfaces, extending pits, and rearranging hazards, so you solve a harder puzzle. Challenge Maps keep the original campaign geometry and score your performance against medal thresholds instead.
How do you unlock the bonus maps in Portal?
They unlock individually and not all at once. Each advanced and challenge chamber appears under Bonus Maps on the main menu as soon as you have completed the matching Test Chamber in the campaign, so you do not have to finish the game first. Developer commentary is the one thing that does wait for the credits.
What counts as a step in Portal's Least Steps challenges?
A discrete footfall, not a tick of movement. Standing still to place portals or move cubes costs nothing, landings only register above a speed threshold, and each mid-move correction adds one. Jumping is not free either, so the efficient pattern is alternating a step and a hop, which covers a long distance for two steps.
How do you get Gold medals on Least Steps in Portal?
Travel through floor portals, but cancel the exit portal while airborne so you land slowly, because a fast landing costs a step. Alternate steps and hops instead of walking, crouch-jump on long stretches for extra reach, and throw cubes to their buttons instead of carrying them. Quick-save constantly, since the counters rewind with the save.
What changes in Chamber 16 Advanced?
Every turret is enclosed in a metal cage. They still shoot, but you cannot pick them up, knock them over, or portal them away, which removes every standard turret answer at once. The cubes are not reduced, and using them for cover becomes the point.
What to Read Next
- Puzzle Mechanics. Fling and momentum tech for gold medals.
- Test Chamber Walkthrough. The base chambers these remix.
- Achievements. Medal-linked achievement requirements.
- Tips and Tricks. What counts as a step, caged turrets, and the shortcut that was removed.