Here are some tips for the impossible : firstly, know that in insane some bosses can randomly speed up and make you get hit : alien,tank1 and spiky tank and golem. However all the other bosses can be easily taken out without taking any hit : cactus(just stay in the upper left)shoot him while he spawns minions, repeat. Beatle : well pretty easy but watch out if you battle it at battle 9 or 10 it will be really hard to dodge when it charges.Ship: go at weak points avoid the white bullets when there are blue bullets just run to the other weak point .repeat The big green monster just repeats the same movements so just memorize them. And put your quality to high !
for 100% of an area you need : all warehouses, full tower, fully opgraded factories and danger at 0% (do some cleanup's it will help) Also you don't need to find all search places. Good luck !
trick for the hard badge.
See the 'avoid the green' minigame ? try keeping it. Very easy when it's the only one left. I managed to get 7.4 multiplier but was tired so died in purpose