I got as far as level seven (the level where you get two castles), found it impossible so searched Google for help. This gave me a YouTube video of someone playing the level through, but he/she started with 120 coins, the GAOTD version only starts with 40 coins! So is the GAOTD version a limited "trial" version, or is there a bug in it?
Also - I was playing the easy version, I tried the hard version to see if you got more coins on that for some reason, and found both "hard" and "easy" to be identical. Again this infers "trial" version.