Very buggy...
Your engine doesn't work right with isometric games like this. You need to do the following...
1. The hole. The hole works like a level part of the field when going at full speed and the ball won't even inch towards the hole when partially there. When going fast, the ball should slightly hop or pop down then up. As for slow ball speed, you should have it in the ball code where when it goes into close proximaty to the hole (setup a test to determine distance from hole) it would slowly inch towards the hole by maybe 1 pixel a second so the player will still need to control the ball speed.
2. The ramps. When the ball goes down the ramp, you had it where the ball goes down in the direction it went into the ramp. Although the horizontal speed increase is accurate, the vertical speed increase is not. You should have it where the vertical speed increases twice it did when going into the ramp piece and become halved when leaving the ramp. You should try different vertical speed increases/decreases to improve this problem.
I know this seems like alot, but when you do an isometric game, this sort of thing for the player to interact properly.