I distinctly recall the game freezing regardless of the height at the end, but that's not what's been happening any more. Now it only occasionally freezes, possibly related to the height at the end, as neonspider says.
This is the strategy I used: get through the first few nets until one is close to either side, then go through hoop and bounce off the wall to get enough height to get to the next hoop. Hopefully the hoop is either near one side as well, or the next-next hoop is low enough down to just bounce to it normally. After you get a combo of three, a trampoline appears which will always give you enough height when you bounce on it. To maintain your combo, if the trampoline isn't close the hoop, bounce on its rim until the trampoline comes closer.
high combos will naturally lead to high scores, which makes score based ones easy.
To get the high flyer medal, get the trampoline, then bounce up and move left and right to gain height.
To get the 3-pointers medal, shoot a few hoops until an easy one appears, wait for 10 seconds to be left, then go thru the easy basket and get four more as they come down on their paths.