This is an awesome game. It's simple and easy. The multi-select makes gameplay extreme and almost arcade like in simplicity.
I do have a few notes. While the speed and strength do an awesome job of upgrading and display, the reproduction and defense seem to do almost nothing. After maxing out, I find truly how unimportant both were at all. The reproduction is a bit of a mystery as some cells cause more than other. I have never seen a defense or improved reproductivity, but I know it's in there somewhere...
And final note: what's with Newgrounds windows? When I click drag the window starts to scroll, and how in the world can I concentrate on the gameplay during this madness. The controls though awesome seem to glitch at time where my mouse over it has no effect.
It's a great game, besides that. I'd be interested for the next, and when interface gets to the next level. Wait a go!