In a word: dull
The gameplay itself was smooth and generally challenging, and there was a DECENT level of customization, but... really, nothing to write home about. The gameplay was uniquish for a flash game, but that dosn't translate automatically into quality. It got boring quite quickly and frankly, I didn't see much reason to go at it again after my second go.
But it's still a decent game. Don't expect it to get game of the week, thou.