Really cool and enjoyable!
So, this game is basically well made. The concept is both fun, addicting and challenging, can't complain there. The amount of courses was a good amount, and that there was some user made levels and that you can make your own ones is a good thing, that makes it take even longer until this game will get boring. You can also challenge rest of the players by submitting your highscore, great job on that too!
But, still........ I think there should be an update, like a graphical update. You know, the game background was a paper, so, do those trees, that sand, that water or that hole match the background? No, I don't think so. Some more "doodle" like graphics could be great, or maybe just replace the white background with a green one. And by the way, maybe replace the squares (sand/water etc...) with something less "squarey". This, of course would make the level editor a little bit harder to make, because that would ruin the tile based system pretty much. Still, what if you have normal tiles and then some border tiles that don't have straight lines?
Other minus must be that I felt like I had to click the submit button a few times too much just to submit my highscore. A small miss.... And yes, multiplayer. How does that sound? For my ears, good. Maybe a cooperative mode, where you "shoot" the ball turnwise, and a versus mode where you fight for the best score. This could be made both online and/or hotseat, so you can play with your friends locally.
But don't think that I'm trying to say that this was a bad game, even if I complained so much about the graphics. I'm just trying to write a helpful review, and I think this was a good game, that definitely would've deserved a higher score than 3.50 which it is on right now. Good game, really liked it.