Berserk gives your hits a bonus equal to the damage percentage you’ve taken
e.g. if your max health is 10,000, and your current health is 8,000, you get a 20% bonus; if your health is 2,500 you get a 75% bonus; when you are almost dead your shots are doing almost double damage.
This bonus carries forward to indirect hits (piercing, chain, etc.) but doesn’t affect the blast damage of the Plasma Cannon