Fine in its own right, terrible compared to Portal
It's hard not to compare Q.U.B.E. with the Portal series. You wake up in a sterile environment and have to solve 3d movement puzzles to get out.
After Portal 2 this game was terribly disappointing, but in its own right, it's OK I guess. The puzzles are OK, but they are not very original. Most puzzles are just 2d puzzles similar to Sokoban or Atomix. There weren't many puzzles that challenged your 3d problem solving like Portal did.
And the puzzles involving magnetism are so extremely annoying! You figure out what you are supposed to do, but still can't solve the puzzle because it all comes down to pushing buttons with extremely precise timing.
Basically it doesn't even have a storyline so you are not motivated to complete an annoying puzzle other than to see what the next annoying puzzle is (in the Portal games you gladly solve ANY puzzle because you really want to destroy GLaDOS:)
However, this game is not expensive and I kind of enjoyed the few hours of play time I got from it. Just don't compare it to Portal:) The game runs fine without any crashes on my 2012 MBA.