Congratulation for your first game jam !
The game was fun to play ! It is may be a little too hard at first and may be it needs intermediate difficulty levels between the second and the third level but I still managed to finish it and it was challenging to learn to drive the ball with parsimony to avoid the spikes without wasting paint. The simple graphics are good enough but it lacks music and sound effects even if the paint particles effect add a nice feedback to the controls.
I also used java for my game ! Which graphic library did you use ?