A like it! Reminds me of tetris crossed with...I don't know, Bejeweled maybe. Attract mode is cute, and the logo makes me think of a Yoshi game somehow. The graphics are not bad at all. (I think the board could use a solid black line at the top, for symmetry)
It's hard to survive very long; I found myself wishing for more 4-square (or even 3-square) pills and fewer plus-es and 2x3s. Once the gray cooties get a foothold, they're almost impossible to stamp out... I think it'd be nice to make things a little easier (or divide into rounds, so that even when they greys are taking over, there's some hope of making it to the next board).
It occasionally crashes on my machine, and it needs a perky little theme song, but other than that this entry is utterly delightful.