In Caromble! it is possible to charge the paddle and give the ball a boosting power such that it will not bounce off objects, but goes right through them. Adding the charging mechanic would make the gameplay more interesting and gives high-score hunters more possibilities. However, we have been struggling with the implementation. How can we strike the right balance between a powerful powerup and not making the game too easy?
In our first implementation, the paddle could be charged in a continuous manner; the more the paddle was charged, the more boosting power the ball would get. If the power was maxed out, we would not only boost the ball, but also give it the ability to crash through objects, instead of bouncing off them. As a trade-off for using this power, we reduced the movement speed of the paddle significantly, making it far more difficult to reach the ball.
For some reason, this did not feel right. Blocking the paddle was too annoying, and it seemed impossible to find the right speed for charging. Either players would charge all balls, or none at all.
Also it felt a bit gimmicky as it was not needed to complete any levels. To solve this we introduced hitable blocks that could only be destroyed with a charged ball.
Now, after several tries, we finally found an implementation for the charge mechanic that feels in place. Instead of boosting the ball proportionally with the amount charged, we only have two possibilities now; the paddle is either fully-charged, or it is not charged at all.
Pressing the charge button (LMB or SPACE) fills the charge meter. While charging, the paddle cannot move at all. When the button is released, the meter empties quicker than it was filled. If the ball hits the paddle when the charge meter is not full, nothing happens.
However, if the charge meter is full, the paddle is charged, and stays charged until the ball is hit. The charge button can be released, and the paddle can move freely. Having the possibility of aiming the ball whilst being charged, seemed to be the missing piece of having a good charge mechanic. It works and feels good. Now all we need is an awesome graphics effects for charging the paddle and boosting the ball.
Because pictures tell more than a thousand words, here is also a video of the Charge mechanic (charge meter in upper left corner):


