Quantum Conundrum is a First-person puzzle video game by Airtight Games and published by Square Enix. It is designed by Kim Swift, who formerly worked at Valve as a lead designer on the critically acclaimed Portal. The game was released on Microsoft Windows (via Steam) on June 21, 2012, July 10, 2012 on PlayStation 3 (via PlayStation Network) and July 11, 2012 on Xbox 360 (via Xbox Live Arcade).
The silent player-protagonist is the twelve-year-old nephew of the brilliant but peculiar Professor Fitz Quadwrangle (voiced by John de Lancie). He is sent to stay with Quadwrangle, who is unprepared for his arrival as he is presently working on an experiment. The experiment goes awry, causing Quadwrangle to become trapped in a pocket dimension with a loss of memory of what went wrong before, but able to watch and communicate to the protagonist. The results of the experiment leave portions of the Quadwrangle mansion in flux between several dimensions with alternate properties. Quadwrangle guides the protagonist to acquire a glove that can tame these fluxes through which he can then safely travel through the labyrinth of rooms to reach three separate power generators and restart each, which Quadwrangle believes will allow him to escape the pocket dimension. As Quadwrangle guides his nephew, he tries to recall the exact events leading to the current situation.
After starting the three generators, the house begins to shake, and Quadwrangle realizes that a fourth generator must be started. The protagonist begins to activate the device, but Quadwrangle remembers too late that restarting the device had nearly killed him before and he had escaped to the pocket dimension for safety. With the device started, the house begins to shake violently, and Quadwrangle instructs his nephew to the safety of the pocket dimension, where he will be safe, while Quadwrangle can now work out how to resolve the problems of the half-ruined mansion. 
Quantum Conundrum is a puzzle game viewed from the first-person perspective. As the boy protagonist, the player can run and jump, interact with various switches, and lift light objects. The player can die by falling into toxic liquids, bottomless pits, or falling from too great a height, and if hit by destructive lasers; this will restart the player at the start of a puzzle or a checkpoint if passed. The goal of each room is to reach its exit door, though may need to activate certain switches or other devices before the exit can become available.
Most puzzles require the player to manipulate the room and objects within it using four different dimensions which impart unique physical properties to the world. The four dimensions include:
- The Fluffy dimension, where objects are ten times lighter than normal, allowing the character to pick up most non-fixed objects.
- The Heavy dimension, where objects are ten times heavier than normal; the player cannot pick up any objects, but their new density allows them to avoid destruction by laser beams.
- The Slow dimension, where time crawls to ten times slower than normal, though the player moves at normal speed.
- The Reverse Gravity dimension, where gravity is reversed, though the player is unaffected by this.
Only one dimension at a time can be accessed (including the normal dimension); when dimensions are switched, all objects retain their existing position and velocity, the latter becoming a critical factor in solving many of the game's puzzles. For example, with access to the Fluffy and Slow dimensions, the player can pick up a heavy safe in the Fluffy dimension, toss it towards a distant platform, and then immediately switch to the Slow dimension, giving themselves enough time to jump onto the safe as it crosses the gap to the platform.
Initially, the player does not have control of when the dimensions are shifted, but later gains access to the Interdimensional Shift Device glove where they can switch to any dimension so long as a battery for that dimension is placed in a power receptacle for that room. In some puzzles, the players must find and locate these batteries; in other cases, the player may have to chose which batteries to insert into place to solve a puzzle.
Late in 2009, some time during the development of Portal 2, co-creator Kim Swift left Valve to pursue opportunities elsewhere. Developer Airtight Games later announced that they had hired on Swift as a project lead, which they stated was a part of their strategy to produce innovative games with a broader audience. Swift wanted to make a game like Portal in the puzzle genre, but worked to distance the concept from Portal to avoid direct comparisons.
In August 2011, Square Enix made comments teasing the imminent announcement of a new project at Airtight Games, with Kim Swift as creative director. This project, titled Quantum Conundrum, was officially unveiled at PAX Prime 2011. During the expo, Swift told the press that her ideas for the game originated from a visit to a local bakery. She said that, like with her previous games, she wanted to create something accessible to a wide market, but with enough challenge to satisfy more experienced players.
The game has so far received reasonably favorable reviews. Destructoid gave Quantum Conundrum a perfect 10 out of 10 score, claiming that "you are an idiot if you don't buy Quantum Conundrum." IGN gave Quantum Conundrum an 8 out of 10 praising the clever puzzles but criticizing "lack-luster" environments and the game's ending. Game Informer gave it an 8.5/10 while praising the game saying "With its physics-warping mechanics, thoughtful brainteasers, and playful atmosphere, Quantum Conundrum should appeal to the legions of Portal fanatics. Some may complain that it’s not as funny or as clever as Valve’s hit series, but Quantum Conundrum is a unique experience that deserves attention nonetheless."
However, not all reviews have been positive. Zero Punctuation has given it a fairly scathing review, stating that "what charms the game has are critically undermined by dull, samey environments and a practical element flawed on both the design and run-time level." Other online reviews have criticized the game for its inconsistent physics, bugginess, lack of changeable visual options and abrupt ending.
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- Hatfield, Daemon (2012-06-21). Quantum Conundrum Review. IGN. Retrieved on 2012-06-22
- Reeves, Ben (2012-06-21). Quantum Conundrum. Game Informer. Retrieved on 2012-06-22