The Bourgeoisie achievement should be Hellish. I couldn't get it until i reset my upgrades to not have Homing Beacon, and even then it took me 10+ attempts to get it
In insane mode level 15 was the hardest imo. When I shot at the boss it took a few seconds to see any damage at all being done on it, so i had to use the mountains to hit it 20+ times. Level 20 (the final boss) was easy compared to this
 "Endless Migration"){kind=icon}
 "The Idiot Test 2"){kind=icon}
 "Epic Boss Fighter 2"){kind=icon}