This is the new game from the creator of Portal, and it shows. Its puzzle chambers are filled with cubes, laser beams, and pressure pads, and a narrator cracks wry jokes as you play. But even though it's just as clever as Valve's puzzler, it's not quite as good.
There's no portal gun; instead you wield the Interdimensional Shift Device, a glove that lets you flip between dimensions. There are four in total: fluffy, heavy, slow, and gravity.
In the fluffy dimension, objects become soft and can be lifted easily. In the heavy dimension, objects become made of weighty metal and can't be moved. In the slow dimension, time is slowed down. In the gravity dimension, gravity is reversed.
This forms the basis of the puzzles. You change the properties of objects in real-time to get past obstacles and traps. If the path ahead is blocked by a pane of glass, and all you have to hand is a heavy safe, switch to the fluffy dimension. This will let you pick up the safe and throw it at the window. Then, just before it makes contact, flip back to the normal dimension and the safe will regain its weight and smash through the glass.
That's the simplest of examples. The puzzles get incredibly complicated, and the interplay of the different dimensions is impressively designed. Like Portal, you constantly alternate between feeling like a genius and a useless idiot. The satisfaction of a puzzle solution suddenly becoming clear never gets old, and many of the puzzles equal GLaDOS' most memorable tests in terms of ingenuity and bewildering complexity.
The problem is a lack of consistency. In Portal there was a very clear, balanced set of tools and rules. If you imagined something, it would always play out precisely as it did in your head because the gameplay was so tightly designed. Quantum Conundrum, however, seems to punish any attempts at creativity.
There are two cube types: cardboard boxes and safes. It makes sense that you can't stand on a cardboard box in the regular dimension, but you can't in the heavy dimension either - even though it's transformed into solid iron. In some levels there are pads that flip you across gaps, but you can't use these while holding another cube.
These are examples of actions that should work according to the physics of the game world, but don't because the game arbitrarily prevents it. Its internal logic is full of holes.