What I can only describe as relentlessly addicting. Judging by the admittedly cheap-looking presentation, it seems like this would be another bare-bones Facebook game formula that by no means should be anything more than forgettable shovelware - but instead this employs one of the most aggressive "Okay, just one more..." mentalities I've ever seen in a puzzle game (to the point where I swore it was my last try 12 consecutive times in a row and suddenly an hour of my day was missing). Just impossible to put down, constant fast-paced frenetic thinking where you can't put your guard down for even a second or it's all over in a flash. Even on easy mode some of the later stages offer a real challenge, and all three modes are excellent. Shame this got ripped off into obscurity because this has been one of my favorite puzzle games for years. Always a good pick-up-and-play blast.