Well done on making the game!
Its definitely a unique idea but the execution may have been better handled for more player engagement;
If I may suggest a few features to take into consideration;
1) Ball counter; I found myself aimlessly throwing balls all the time to with no care for precision timings etc... I would suggest Limiting the number of Misses a player can get (ex; If the goal is get 10 balls in, you only have 13 balls to throw, thus enforcing the player to really calculate his shots)
2) Score System; Having diff points for areas on where the ball enters the crate, giving a sense of accomplishment and reward for achieving "Bullseye" shots over barely hitting the edge of the box.
3) Game feel; Look into making the actual ball shots more interesting; with better SFX and maybe some slight camera shakes on successful ones; Just to enhance the enjoyment for the player
Well done once again! ^^