Good start/Effort..
Well im going to offer a constructive suggestions to make it better.First of all i don't like the fact that goblins are tougher than knights and trolls - trolls and knights should be tougher than goblins.Secondly i don't like the arrow thing, it's hard to dodge it - make the arrow smaller(since when were normal arrows as big as people?).Thirdly i would like to mention the sound as you can see i gave it a 3...make sounds when you fire and when the beasties die other just than hearing the arrow and the castle being hit.Now finally, make more upgrades - like archers or even wizards on the castle ramparts and also make more enermies.To say overall it was decent but could have been better - lets hope my suggestions can help you.