Hatsworth is easy if you unlock the big bomb (it's unlocked after you finish all of the castles - it doesn't matter what medals you have, just finish all of the levels.) with the big bomb just aim for the second level of the castle and the whole thing will topple.
I really like this game. It's fun. I was able to get gold in all of the first lands, but when I got to Betsonia, the last group, it was too hard. I just got through it (sometimes with 20 shots, lol) and when I finished the final castle, I unlocked the big bomb. Now, I'm going back thru Betsonia with the big bomb and getting gold usually on the first try. I'll have final badge in no time.
I wish I could like this game. I really do, but it's not fun to me. It's very well-made. The animations are cool. It's unique. It's just plain not fun. It's tedious after level 2.
4635 is the best I can do. I keep missing windows. I suck so bad at high speeds I have to purposely run into things to slow me down... that being said I still like the game. Cool atmosphere to it.