It’s like Minesweeper, but with hexagons. Hexcells is the better of the two, by far.
The game may not be particularly impressive, but it does serve as a great time waster, especially for those that prefer to keep their brain active whilst playing a game. Hexcells, being a puzzle game, does a fantastic job at this. Some of the puzzles are easy, some hard. A great balance is struck between the two. If you’re looking for a real challenge, go pick up Hexcells Plus, which is a standalone expansion pack of Hexcells. The puzzles in Hexcells Plus are a bit more difficult, but still manageable for the most part.
Although the game may be fun, the amount of content offered is rather small (well, that is if you’re going in without Hexcells Plus). I can recommend it, but don’t expect the game to last too long.