I like that you can choose to either take is slow or you can absolutely maximize the amount of points you get. Purple flower box combo for the win!
The music loop is a little too short, it gets a little annoying after a few levels.
About 4 levels in the economy of coins gives you too much, so you can always buy all the cards. Maybe this could be balanced by having expensive gold versions of the cards that have extra ability or combo?
For me the button to go to the next level never hides, so I can just keep clicking it and continue into levels even if i don't have the right amount of points.
This is a very solid basic game concept. You could take this and add several game modes. One one side you can have timed build, where you want to keep going to as many islands as possible. On the other side you could have a limited turns mode, where every card placement is carefully chosen for extra points.