Nice game. Graphics are very nice.
I have some suggestions:
- Music would be nice.
- The gameplay could be faster. The balls can fall at a faster rate.
- A skip button for the start, when you are ready with the setting and want to start the wave
- New types of balls, like some fire ones which burn the wood.
- A level overview to play older level and a score system with medals and a highscore.
- A goal for the game. Since it's a priest, you could let a demon fire the bullets or something like that, maybe gather faith as a score alternative.
Keep up the good work!