In singleplayer, a decent puzzler, though one prone to screwing over the player on higher levels. The act and cadence of dropping pills and clearing viruses is fine enough, sort of fun to orient your brain around that level of pattern recognition. But the only real way difficulty scales is by increasing the amount of Viruses in the well (on top of the Doc throwing faster pills as the match goes on).

At higher difficulties, the viruses are so high that it feels like a player's ability to clear the well is based on where the Viruses happen to spawn. Hard to stay on good terms with a game that, 9 times out of 10, decides it's gonna give the player an unfavorable game board without anything they can do about it. I think the game is at its best around levels 10-15, where there are enough Viruses that the player has to think about it, but not so many that the above scenario happens.

Decent animation and quite good music, though. "Fever" is of course the enduring classic, but I actually find I like "Chill" better, at least in this original version. Something about hearing that driving groove match pace with the Viruses' dance adds a good deal to the experience.