Oh yes, the mouse wheel adjusts the shot power. Hopefully, most players know about that.
What some players might not know is that SHIFT-mouse wheel is the fine grained adjustment of the shot power.
CTRL-mouse wheel is also used: it adjusts the cue elevation angle! It's very handy to line up a hampered screw shot, for example, and you can keep the mouse at the bottom of the Qball while CTRL-mouse wheel-ing the cue elevation angle up by a couple degrees, until the red cue tip dot turns into the usual grey tool tip, so you can take that screw shot.
The next version of the game will show all such tricks and shortcuts in a window.