Hmmmm
While I understand the effort it takes to make a game like this, I didn't think it was anywhere near as good as it could be (or as good as DYC, on which it was obviously based). I thought the drawings were quite crude, the choice of text was awful (looks OK in fullscreen, but otherwise, blehh) and the text boxes could have been arranged better. In the DRAG option, you can still drag the attackers after you've killed them (for example, the tanks whilst they're in the process of exploding); the archers & gunners did virtually no damage, and the spells were too powerful - too easy to wait until they almost hit the castle, chuck a meteor and then fireball at them and bang attack over.
But the biggest problem of all is the LENGTH of each attack. You have more attackers to deal with, but they all come onto the screen within 10 seconds. You really have to stretch the attack out longer as the levels go up - that way, the charge bars for the spells will actually have some use. You should also stop the bars from charging between levels, as that makes it all too easy, too.
Don't get me wrong, I do like the game, and played it for a couple of hours - but it needs some major bugs ironing out, and a little more depth adding.