The biggest, most badass, most brilliantly designed ever made tower defense game.
Has a sequel - http://armorgames.com/play/15760/gem...hasing-shadows
Been playing it for a few days - it's still got some bugs going on, and it'll need some tweaks here n there, but it's been long awaited and figured it needed sharing with the lot of you.
If you never played gemcraft yet, the game conveniently allows you to see the earlier versions as well.