There are games that age gracefully, and then there’s Portal 2. Even more than a decade after its release, it manages to captivate players with its sharp humor, clever design, and deeply satisfying puzzles. But what truly surprised me on my first playthrough wasn’t just the game’s charm—it was the realization that Portal 2 includes a built-in level editor. The ability to craft your own puzzles directly within the game opens up an entire world of creative expression.

This article documents my first attempt at puzzle design in Portal 2, the missteps I made, the lessons I learned, and why nonlinear thinking is at the heart of great puzzle experiences—not just in this game, but in puzzle design as a whole.

The Illusion of Complexity

At first glance, creating a puzzle level seems almost too easy. You place a box, add a button, connect it to a door, and you’re done. It works. It’s functional. But it’s also boring. So the natural instinct is to spice it up. Add more buttons. More boxes. Maybe throw in some repulsion gel or a pit of goo for flair. Why not fourteen buttons? Fourteen boxes? Surely that’s a challenge.

And yet, if someone actually played that monstrosity, they’d likely quit out and leave a scathing comment. Why? Because complexity does not equal depth. A level that simply asks players to press more buttons doesn’t necessarily make them think—it just eats up time. Real puzzle depth doesn’t come from quantity. It comes from structure, from subtle misdirection, from clever interplay between intuitive assumptions and actual mechanics.

Understanding Linearity

Let’s take a step back and look at the idea of linearity. Imagine a level where there’s a button and a box. You use the box on the button, the door opens, and you’re out. That’s a linear puzzle. The solution is the first thing most people will try. It’s direct, immediate, and requires no reconsideration. You can dress this up a bit—maybe pressing that button activates a light bridge, which then needs to be deactivated by another button to reach the exit. But still, all you’ve done is string together two obvious steps.

That’s the trap: stacking linear puzzles doesn’t create complexity. It creates a longer linear puzzle.

How Nonlinearity Creates Engagement

So what makes a puzzle nonlinear? In a great example from Portal 2, I encountered a puzzle involving three lasers and two reflective cubes. At first, my intuition kicked in—I used the cubes to redirect the lasers to their sockets and tried to complete the puzzle. It didn’t work. There weren’t enough cubes to make all the connections. For a moment, it felt impossible.

But then I paused and began to think differently. What if I didn’t need three cubes? What if one laser could go through a portal, removing the need for a third cube entirely? That shift—where the initial intuitive solution fails and forces you to engage deeper problem-solving faculties—is where nonlinear design thrives. It’s not about being obscure. It’s about forcing the player to adapt.

Your job as a designer is to trick the brain into thinking one thing, and then gently push it toward a better answer. Not with brute force or trickery, but through structure. Importantly, every element of your puzzle must still be clear. If you include fourteen buttons and only one of them does anything, you’re not being clever—you’re being frustrating.

Designing My Own Puzzle

When I started building my own level, I began with that same classic idea: a box on a button. Then I slowly started breaking it apart, twisting expectations, and trying to make something more engaging. Along the way, I discovered just how difficult it is to design nonlinear puzzles that are still fair and solvable.

The final version of my level begins with a clear visual language. The first thing players see is a button that opens the exit door and inverts the polarity of a tractor beam. Then, in the center of the room, another button drops a cube—but it immediately falls into a pit of goo. On the far side, there’s some repulsion gel and a brightly lit portalable wall, almost begging to be used.

So, naturally, the player’s intuition suggests a solution: place one portal at the end of the tractor beam, the other on the portable wall, and then drop the box to catch it midair. But here’s the trick—once you’ve set those portals, you can’t get back to the middle of the room to actually drop the box without breaking your setup. The puzzle seems impossible.

And yet, it isn’t.

Why Playtesting Matters

When designing this level, I learned two critical lessons. First: always playtest. Not just for bugs, but to check for unintended solutions and make sure players are pushed to think the way you intended. Second: clarity is everything. Originally, I had placed the button closer to the gel, which let players almost reach the middle of the room via bounce—almost. But not quite. This led some testers to think that was the solution and then get stuck.

By moving the button farther away, I removed that ambiguity. Now it’s clear that bouncing there isn’t the way forward, encouraging players to find the true, more elegant workaround.

Conclusion

Designing nonlinear puzzles in Portal 2 is not just difficult—it’s humbling. It’s easy to think of a solution and harder to think of how others might approach it. It’s even harder to guide them away from the obvious path without frustrating them.

But that’s also the magic of it. A good puzzle doesn’t just challenge your logic. It challenges your assumptions. And the moment a player goes from “this is impossible” to “wait… what if,” is the most rewarding moment a designer can offer.

If you’re curious, you can try my puzzle yourself. But be warned—it might just fool your intuition.

Let me know your thoughts in the comments. Until next time.