Kyle Orland at Ars Technica:
Great games generally fall into two groups. The first group is what I call slow burns: games that often take hours of introduction, explanation, and learning before the experience really blossoms into something fully knowable and enjoyable. The other group is those instantly accessible gems. The basic gameplay is understood in minutes, but you can immediately tell that the strategic and gameplay variations inherent in the design mean you'll be putting in hours or days of play time into mastering them.
In my experience, this second group of great games is much smaller than the first. Titles like Ms. Pac-Man, Tetris, Super Mario Bros., Geometry Wars, and Spelunky fit the description for me. Whatever your taste, though, it's not often that you find a new game that you know will become a true obsession only a few minutes in.
Let me tell you, Threes is one of those rare games.
It's true. Vaidehi and I can't stop playing.