I guarantee you that if you've never played basketball and tried to make the same shot over and over again, the ball would go in different places every time. Only people who are actually good at basketball can make the same exact shot every time.
Seriously you need to just practice. The game's "controls" are perfect and respond exactly to what you do. You may think you are doing the same shot but if it's doing something different, then YOU are doing something different. The game is
based on your ability to judge trajectory and shot strength, there just is no indirect control like in Angry Birds (where the (x,y) location determines speed and angle). Your finger speed determines speed and the angle at which it moves determines the angle. It's not like the physics engine sporadically changes every few seconds requiring a different move.
A tip is be hyperaware of when/where you touch down and release your touch. This is equal to you holding onto the ball, meaning forces are being applied to the ball object. If your finger speed and angle are the same every attempt but the time in which you are touching the ball changes, the outcome will also change!
Originally Posted by Misguided
If I make what I believe to be the same, or very similar, motion several times, but get wildly different results, there's a problem.
"very similar" does not equal "same". If you are getting wildly different results, you need to focus on making more minor adjustments. Just like in the real world, changing the angle of approach from a bouncing object can end up translating to drastically different angles later on in the bouncing objects path.
Ever play pool/billiards? Same thing happens there! If you adjust the angle of the cue ball by only a single degree, you can end up changing the angles of the other pool balls by much more than that as more and more objects collide and the system becomes a bit chaotic - yet there are pros out there who can sink any ball they want at any time!