Nice concept, could be deeper
I like the castle defense concept, of course, but I have a few problems with this game:
1 - The big enemies with lots of HP, when alone, didn't add much to the game, it's just long to kill, and gets boring to dodge.
2- There SHOULD be a way of increasing permanently damage. I didn't get the high level spells, so i dont know if one does make that, but it would be a great plus.
3- As said before, the lack of diversity in attacks (there is not THAT much spells, and we only have a single normal attack) did affect my appreciation.
As a suggestion, if you want to improve your game, i would do as blades-of-ownage and suggest you to add classes, upgrades, equipment, stats, ond whynot including a money concept, to hire soldiers and mercenaries to help...
Otherwise it's a great game, lot of potential in it!!!! Good job!