Someone send help; I'm addicted to Trixel! Stopping to write this review is killing me!
Well, OK, it's not that dire. But Trixel, the new puzzle game by ADEPT Games is rather enthralling. It's really simple to pick up, and somehow manages to be both easier and harder than you'd think. The object is simply to flip the colored tiles on the screen in order to make the pattern match the design shown in the upper-left corner. Sounds like a snap, right? However, most of the time (unless you get a warp tile or something; we'll come back to that), you can only move between adjacent tiles, and any tile that you land on will flip, so often you'll find yourself having to double back in order to get all the colors right.
Oh, and did I mention that there's a limit to how many moves you can make? Tricky!
With 100 puzzles and three difficulty levels, the replay value of Trixel is pretty much massive. There are also, in many puzzles, crystals to be collected. Not only do crystals allow you to purchase various special abilities and cheats (well, I guess they're not technically cheats, more like power-ups), but completists will definitely want to replay puzzles until they've collected them all. Additionally, when you complete each puzzle, you get a souvenir in the form of a bronze, silver or gold cup, and I know I personally won't consider Trixel beaten until I have a gold cup for every level.
Probably the biggest thing that separates Trixel from most other puzzles out there is all those special tiles and added abilities, ranging from tiles that simply allow you to move diagonally to tiles which have bombs which blow up (and flip!) a bunch of tiles in range. The different bonus-type moves and tiles help keep gameplay fresh and exciting. Trixel also has a "Race the Clock" mode - sort of a "sudden death" round in which users solve as many puzzles as possible in a set amount of time.
All things considered, I would say Trixel is one of the absolute best puzzle games out there, and I heartily recommend it.