People like to compare this to Portal because of the similarities in first person puzzle and level designs, lighting and more, but those do Portal injustice because Q.U.B.E. doesn't have an overlying story narrative, you never break out of the "test" environment, and there is usually only ever one way to solve each puzzle. With those things said, Q.U.B.E. is still a fantastic puzzle experience, and other than some frustrating moments in harder puzzles towards the end where you have to repeat gameplay too often, it does a great job at gameplay, and stands alone.
I think the reason Q.U.B.E. works is that it knew it probably couldn't beat Portal in terms of story, design and gameplay, and instead focused on just making the puzzles and experience simple and focused, but fun.
* Great use of lighting and colour which keep a minimalist feel, similar to that of Mirrors Edge, but allows for some more interesting art style when needed
* The nice ambient soundtrack and lack of rush or impending action keep things mellow and smooth and match the visuals
* Tutorial elements and introductions to the mechanics feel natural and are well implemented
* It's a short game, but still feels slightly repetitive towards the end due to the lack of variety in mechanics. Breaking up the puzzles with more platforming, or more interesting segments would've went a long way
* The narrative added in the Directors Cut is a pointless addition and takes away the atmosphere and isolation
Available on Steam for £6.99/9.99€/$9.99 at the time of review and clocking in at around 4 hours of gameplay, it's a fair deal when on sale.
There were originally two versions of Q.U.B.E. available, the original and the Director's Cut which added Oculus Rift support, a couple new puzzles and the 10-level time trial mode DLC. Unfortunately it also added a poor narrative, which adds very little and takes away from the games mysterious, isolated nature. Copies of the original Q.U.B.E. may still be available on other sites and, if you can, I strongly suggest tracking it down instead. It's an annoying and frustrating business practice when a publisher adds things that actively harm the game, then forces you to buy them over the original, especially when it's nearly twice the price. An optional DLC would've been a far better choice here.
However, Q.U.B.E. is still a good game and remains fair value for money, if it's on sale, it's a great buy.
* A sequel, Q.U.B.E. 2 is being developed in the Unreal Engine 4, the details of which are being kept closely guarded