It has promise but needs alot of work
I was really looking forward to the game but once I started playing it I was sadly disappointed. 1- The tutorial was a little lacking although it was easy enough to figure out. 2- The first bunch of times I played it I couldn't even get past the first level! I was trying to use some good strategy but in the end you have to be cheap, (ex. creating a huge amount of upgraded infantry or archers only) you own the castles and it's not really fun to play. 3- The scenery really needs to change once in a while, I mean it's looped enough with the same strategies. 4- Instead of the castle just having one more cheap archer every level and some water bucket thing, try and change it up a little. I mean you could even make the maps with different paths to the castle, you could add enemy units in the field, and you could specialize the units (ex. a ram can break a hole in the castle and the infantry can enter, you could add an infantry mini-game and lost of other stuff, I mean you would have to do some optimizing but it looks like you didn't in this one anyway. And just so you know I'm not attacking you or your game, I love defense games and can see this being awesome, you just need to work on it. I truly look forward to number 4.