Really cool concept! Usually I'm not a big fan of golf, but this was a lot of fun! (It was also super satisfying to get a hole in 1 on the second level. 😎)
I didn't realise at first that the gradients represented hills. Firstly, the fact it goes from light to dark reads to me more like it's going downhill rather than uphill. Secondly, the fact this gradient only applies to the hills and not the whole level seems a bit inconsistent - I wonder if it would read better if the shade of the green for each area indicated which height it was on, with darker meaning lower and lighter meaning higher, and the hill gradients reflecting this as they provide a transition between heights.
Also, shame about the game-breaking bug halfway through! (Especially how you were able to fix it but missed the deadline by mere seconds! I feel for you there haha.)
Overall, I really enjoyed it! The gameplay is fun, the graphics look great and the audio adds a nice and satisfying extra layer of juice. Nice job! 😄