Aesthetics are key in a game like Quantum Conundrum, even if screen filters make up 90% of them. Each dimension has its own texture and color scheme. Switching to Fluffy turns almost everything into a white gossamer wonderland, switching to Heavy turns everything into an oppressive crimson metal wasteland, and so forth. The visual tricks don't end there; Quantum Conundrum casts you as a child and drops you into a mansion that is as impossibly complex and dangerous as it is huge. You feel this from beginning to end. You are small, and this place is enormous. That being said, Quadwrangle Manor is surprisingly full of empty spaces, corridors, and staircases. This leads me to a small nitpick: if Portal was able to cut the fat as thoroughly as it did, why couldn't this game? Too much time is spent getting from room to room, and not all of these transitions are smooth. Some are great, however; pictures on the walls are full of detail, and switching dimensions while looking at them provide some of the biggest laughs in an already funny game.
Portal 2 did some truly incredible things with sound and music design: things that very few developers have even attempted. Quantum Conundrum could have done the same kinds of things, but sadly doesn't. The soundtrack is comprised of a rather boring series of synthesizer tunes. The voice acting is handled by a single person: John de Lancie of Star Trek and Breaking Bad fame. His performance as Fitz Quadwrangle is a lot of fun to listen to, but let's face it: his character is going up against GLaDOS, and that automatically puts him at a disadvantage.