I played it a lot, it's really addictive! I died shortly after round 36 on both runs, I though I had a good strategy the second time around but I guess not..
A few nitpicks: The thing that shows your lives looked like an obstacle at first because the cannonball path goes under it. I didn't really get why the timer only works on the last ball which made me get some items that turned out to be not as good as I thought. The boss stages say that you need "double" the score so at first I thought I had to have double the target but it just calculates it for you.
I really like how you can combine items even though I didn't understand it all that well at first and I'm pretty sure I made some of my items worse the first time I tried it. It opens up a lot of possible combinations, especially if more items get added later on.
Good work so far, I'd like to see more in the future. Curious what the 3d area is going to be used for