Very nice game! some suggestions though...
i agree with andy374. Too Easy. as the levels increase, the difficulty should increase as well. maybe you could have a giant hand come down and fling your soldiers into the air!!! the main point is, make the game harder and harder. it would be great if you mademore ways your units die, or even making more available units you could make. Ex. (catapults, cannons, magic guys, etc.)
or maybe you could make this a game where you deafet other castles while defending your own. and after that, you could make an online multiplayer version!! wouldn't that be great? yes it would. well n e way, i hope u dont explode or get shlashed in your sleep or die in a flood, or get brutally murdered while you were in prison for sexually harasing a co-worker who just "wanted to be friends" but i knew she wanted me! i knew! I KNEW!!!!! so good luck...