To whoever is having trouble with the boss:
1) Buy all upgrades
2) Destroy the blue guys and purple guys without getting hurt
3) Wait for boss to stop shooting
4) TRUST ME: Run in the middle of the boss
5) Use slow-mo. and berserk while inside him
6) Repeat
 "Amorphous+"){kind=icon}
 "Death vs. Monstars"){kind=icon}