Another great game I started back in 2015 and I'm finishing only now, three years later. Well, that insane mode is indeed insane. If you wanna do the impossible badge, I definately recommend you trying with the robot suit, otherwise you will suffer a lot just like me trying to do it with Blast. But if you wanna challenge yourself really hard, pick up him. Some bosses have some exploit points, where you can stay without being hit, like the Cactus (behind him) the Alien (also behind when it shoots lasers) and the Spaceship (in the middle of the screen, when it is attacking with white beams). You gotta get luck to get a run where they repeat twice or more and the harder bosses, that you have struggle with, don't appear to much or appear in the end, when they have more health and inflict more damage. For me, the hardest ones are the Drill Tank, the Eye and the Stone Man. I've killed more than 504 bosses and if I have beaten the Drill Tank 5 times, is a lot. I wish you good luck!
Started in 2015, got 96%. Now, after 3 years, in 2018, I finally went 100% and achieved the Golden Duck! :) If you wanna do the impossible badge just don't give up (like me three years ago), because the layout of the areas are basically the same every run, so you can learn some of the patterns and how to doge them. I would recommend priorize the combos in the earlier areas and then focus in getting no hit by the enemies, but if your combo is 15+, killing foes is more rentable. Just be patience and practice a lot, I'm sure you can do it.
When you complete 100% of the game, you unlock the Serpent Blade, which kills any enemy (except the bosses) in one hit.
Very nice game! I really would enjoy spend more hours playing a third Cactus McCoy. :)
 "Epic Boss Fighter"){kind=icon}
 "Rogue Soul 2"){kind=icon}
 "Electric Box 2"){kind=icon}
 "Cactus McCoy 2"){kind=icon}
 "Toxers"){kind=icon}
 "Jumphobia"){kind=icon}