Good abstract strategy games are very hard to design, because they depend at their core on a small number of easily learned mechanics that breed a high level of strategic complexity--think Chess and Go. Wu Hing is a nicely polished such game--reminiscent of the work of Sid Sackson and Alex Randolph (the finest American boardgame designers of the mid-20th century).
Wu Hing is played on a hexagonal grid; each player (you and the AI) has a "hand" of tiles, replenished as tiles are played. Each tile represents one of the five classic Chinese elements (wood, fire, earth, metal, and water). A mandala displayed at the upper left of the screen explains that each element can "create" one other element, and also "destroy" a different element. (Think of this as a variant on rock-paper-scissors, with five rather than three elements, and with two outcomes--"create" or "destroy" rather than a single one--"beats".)
By placing two tiles of a single type, both adjacent to a tile you own of the "created" type, you can "create" it, removing it from play, and scoring a point. Similarly, by placing two tiles of a single type adjacent to a tile of the other player that they "destroy," you can destroy it, removing it and scoring a point.
Additional points are scored for "balance"--both creating and destroying a single element, creating or destroying all elements, and so on.
Finally, there are some special tiles--e.g., ones that change ownership of a tile already played, and "wild card" tiles that can be used to represent any element.
Sound simple? Yes, of course--but in common with other good abstract strategy games, simplicity of rules set does not mean simplicity of strategy. Figuring out how to optimize your score given the tiles in play and the need to take advantage of additional scoring for "balance" is non-trivial. Indeed, it's likely to take you some time before you begin to understand the strategy of the game. "Easy to learn but hard to master," in other words--a cliche, to be sure, but one that's appropriate to this game.
Add a simple but elegant graphic design, and a somewhat new-agey sound treatment, and you have appealing game of a rare type in digital media.