In level 1-5 you are tasked to bowl with Wall Nuts, to take out zombies. I see that the wall nuts bounce, but they seem to bounce randomly. It seems like it is important to get multiple hits with each Wall Nut, but I can't figure out how to make it bounce up vs. down. Can it be controlled?
From my own experience, you can't control which way it bounces.
From plantsvszombies wiki:
...the Wall-nut will bounce off at an angle, possibly hitting more Zombies before it rolls off the screen. It will also only bounce off towards the right as it does not make sense for it to go backwards...
It says nothing about which direction it bounds, up or down, so my guess is that it's somehow random.