Portal 2
Doppelgänger is a solo level design project focused on creating an authentic Portal-style puzzle with clear mechanics and player-driven problem solving.
Doppelgänger
I made earlier designs too complicated by stacking multiple twists in a row, which made the level much harder to design. I learned that puzzles should be built in a step-by-step process to stay clear and understandable.
Keep It Simple
Design Intent
Designing The Twist
I started by defining the twist of the puzzle. Most Portal levels end with the player pressing a button, so I wanted to invert that expectation by having the level completed through the removal of a cube. To support this idea, I used the cube dispenser system, which typically exists to prevent softlocks by spawning a new cube when one is destroyed. Instead of treating this as a background mechanic, I built the puzzle around it, turning an overlooked mechanic into the core solution.
Too many ingredients scatered around the room hurt the cohesion and twist.
Unexpected, Interesting and refeshing
Common, predictable and basic
Looking Back
Looking back, this Portal project was a really enjoyable experience. I liked challenging myself to come up with a strong puzzle for a game I’ve enjoyed for a long time. The process felt very user-friendly thanks to Portal 2’s level editor, which made it easy to quickly test ideas and iterate.
Designing the twist, where the player’s first instinct is wrong, was especially valuable. Working backwards from that idea and placing small breadcrumbs throughout the level made me realize how much thought goes into player guidance. It also showed me how powerful good level ingredients are, as they give a lot of freedom while still supporting clear design.
If I could redo the project, I would focus more on the level layout and player guidance. Some interactions are placed too far apart or out of view, which hurts clarity. The level is also quite large, and moving around too much can slow the player down, especially when they are trying to think. Despite that, I’m happy with the result and see it as a strong learning experience.
Level Breakdown
Explanation
Here I will explain how to beat the puzzle step for step and the intent of each interaction . Spoilers ahead!
Step 1 - First view
1. The player enters the room and immediately sees the open door across the water.
2. To the right are several turret lasers indicating that the turrets watch over the water.
Step 2 - Introduction
1. Once the player turns the corner, they'll see a laser and a cube with a dispenser.
2. To the right is some glass which might have something behind it.
Step 3 - Glass
1. Looking through the glass reveals a laser receiver with an icon and the turrets from before.
2. Behind the player is a hard light bridge with the same icon. This teaches the player that icons linked ingredients to each other.
Step 4 - Interactions
1. With only one option, the player can use the cube to shoot through the glass, teaching them that lasers go through glass.
2. The player might (accidentally) hit the turrets, teaching the player they also use lasers as a weapon.
Step 5 - Player Choice & Small Twist
1. The player can now choose however they want to cross the water with the light bridge using the many portal surfaces.
2. If the player hasn't destroyed the turrets, they will learn the hard way. Remove them and try again.
Step 6 - Run It Back
1. Entering the new room, the player will see the ingredients which have already been introduced.
2. Players with a keen eye notice that the exit door is again open and is activated by the laser on the right.
Step 7 - Familiarity
1. One of the rooms is full of turrets which should be familar to the player. More turret lasers to the hide indicates more space.
2. Use the 2 cubes and your portals to guide the laser and destroy both sets of turrets.
Step 8 - Misdirection
1. Placing the laser in the receiver will activate the stairs to the exit door which is in view.
2. Using the button next to the exit door will destroy the cube, lowering the stairs again. Confusion is expected.
Step 9 - Thinking Outside The Box (Literally)
1. Players might be confused on how to activate both the stairs and the doors.
2. The "Ah Ha" moment comes when the player recognizes that they need to switch the cubes, which is where the other ingredients come into place.
Step 10 - The Ol' Switcheroo
1. Using the other receiver, the player can get the cube over the fizzler. Now the player has a portal on the other side.
2. Switch the cubes while keeping in mind which one is which and repeat Step 8
Step 11 - Gratification
1. Press the button and watch the switched cube disintegrate.
2. Now the laser can hit the receiver to open the door.
Step 12 - The End
1. Turn around and watch the door magically open.
2. Enter the elevator and finish the level.
Level Overview
Layout
The level is mainly designed around the laser and the cubes that redirect it. The activator for the stairs is placed on the opposite side of the level, forcing the player to use portals and the cube to reach it.
To the player’s surprise, the end door is already activated, creating a conflict where they try to keep both laser activators active, which is the player’s instinct and therefore the wrong solution.
An onboarding section introduces players to the basic portal mechanics using the same level ingredients in a simpler way.
Level Ingredients
Portal offers a wide variety of level ingredients, but to keep the level cohesive, I intentionally selected only a small set to build around. Not all ingredients work well together, so limiting the palette allowed the mechanics to feel clear and naturally connected, resulting in a more focused experience.
Lasers are easy for the player, acting as a simple shoot and receive mechanic. The player might not know what the receiver does at first, creating a small aha moment.
Redirector cubes synergizes with the laser, letting players find creative angles to hit receivers. Fizzlers block cubes and portals, making them useful to force new routes.
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Light bridges allow for freedom of movement and add verticality. Turrets act as basic enemies, and removing them with lasers is a fun interaction.
Hard Light Bridge & Turret
Redirection Cube & Fizzler
Laser Emitter & Receiver
Project Role
This Portal 2 level was developed as a self-study solo project at BUas. The goal was to design a puzzle-focused experience using Portals level ingredients, emphasizing readability, player understanding, and satisfying problem solving.
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Utilized Portal's existing mechanics to create a puzzle.
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Playtested and iterated with the Portal community
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Built the entire level layout
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Structured the level to support onboarding, discovery, and solution
Portal 2
Solo
1 Weeks
Level Designer
