10 Video Game Puzzles You Couldn't Solve (Even With A Guide)

If you don't know how to solve a puzzle in Portal, you can be stuck for an hour. But if you know what to do, you can normally whizz through a section in a matter of seconds.

However, Test Chamber 18 is a little different. Because this level is filled with turrets, insta-kill slime, a cube, slow-moving platforms, easy-to-miss sections, and shifting panels, you know you'll have your work cut out for you.

Although a tutorial video will show you how to get out, actually pulling it off is a different matter altogether. In the final stages of the puzzle, you need to press a button to raise a panel on the other side of the room. After that, you need to teleport yourself beside the panel and crawl through it while holding the cube.

The problem is that the cube is so bulky, it can easily catch on the panel, preventing you from passing through. Even if you know precisely how to complete the task, it's the one moment that's sure to take the most experienced players five or six attempts to complete. Because of this, it's no surprise Test Chamber 18 is detested by speedrunners, since the slightest error will jeopardise their run.