This game doesn't have a chance without a power meter and a score card. Also, the holes are very similar to other mini-putt games. Try to do something a bit different.
I suggest making the first level beatable. Ease us into the game. I tried to beat the first stage and quit after a few minutes because it was frustrating. Start us on some real easy levels to get us invested in the game and gradually make it harder.
Kudos.