At higher percent bonuses the button is pretty much easy stuff. Just simply buy all your boosts up to about max, and start hitting that button like crazy (use your non-primary hand to click while using your main hand (right?) to do other real life things)!
"Shoot from different angles"
I would do so if the ships didn't always f**king face towards you, turning at lightspeed. This is why they are impossible to kill yourself.
You seriously need to make enemies come if you don't kill off the current wave for a while. I found it very possible to just wait on an enemy and try to avoid killing it, therefore minimizing the challenge of finishing the timed levels.
I actually managed to cheat on the third level. I simply went off the cliff, jumped in mid-air to carry me some more distance, moving left all the way. Eventually when I landed, I landed on the victory platform and there I go.
I have a bunch of things to say.
First of all, I only needed 128 continues to beat Insane (apparently that's a 30 point score). It felt like I needed about 500.
Second, to base insane mode you have to utilize both uncontrolled falling back and moving left. What I mean is, you need to both press left to move leftward and left go and fly back. Flying back makes you move quickly, which is useful for grabbing plane ticket money, but moving left is perfect for avoiding obstacles as this puts you in a state of movement exactly the same speed as the obstacles.
Thirdly, I agree with pwntjoo. Some challenges, like the one where you're riding the plane avoiding geese and avoiding pillars on the whale or whatever posed no problem on Easy or Moderate, but on Insane even they required a couple of tries.
For the really highly detailed ones, like Master Chief and Samus, when we load them perhaps a button should temporarily appear to just skip all this drawing and head straight to the finished product, or speed up the drawing by a lot.