This game is a Flash masterpiece. It builds really well on the formula set by the original with a new setting with unique new enemies and top-end tower upgrades.
Not only that but the graphical style has become even more interesting with the desert setting and the unit themes matching the setting, well done!
I think the best quality of this game is the soundtrack, it's fantastic! I don't know what wizardry they worked to make it come out so clear through flash but being used to muddy, distorted soundtracks from other games I was blown away when I first started the game and heard it through my Sennheiser 598's. It's a shame the voice acting doesn't come through as clearly as well but I understand there's a limit to what you can ship in a nearly 60mb (!) flash game.
5* Graphics and Art style
4.5* Sound
5* Gameplay, very challenging but not unfairly so.
My rating: 5*