I like how this entry is very unique - I don't even know when I've last seen a game inspired by mini golf!
However, I see a lot of room for improvements here. Firstly, the grass mechanic could've been a little more polished. You can completely ignore it and play normally, and it even makes the game easier because you can use the tall grass to instantly stop the ball. I know the player is supposed to beat the levels with as little moves as possible, but the players will ALWAYS take the easiest route - in this case, abuse the grass to make the levels easier. Also, l wish there was a shortcut to switch modes since moving the mouse around at all times is kinda annoying imo. Lastly, clearing the grass should be easier and more satisfying, as the ball can collide even with the smallest piece of grass sometimes.
Adding to my previous gameplay point, there's little motivation to play the game the way it was intended to. But adding a really simple score system would fix a big part of that problem.
Anyways, this is a step in the right direction, great job!