Antichamber. It's minimalist, confusing, and fantastic. The easiest way to describe it is to imagine that the labyrinth in the movie Labyrinth swallowed the Portal games but left all the muppets and David Bowie behind. The design is sharp and physical laws of matter are completely disregarded for the player's benefit. I would definitely recommend it as both a puzzler and an exploration game.
HBA: Live #1 Antichamber Blind
HBA: Live #2 Antichamber Spoiled