Boss 3 is now complete. He is normally immune to the players bullets however he is not immune to his own rockets witch the player has to hit back at him. Each time he is hit he gets more angry and aggressive until he eventually gets rid of the floor. The only way to survive is to jump across very thin platforms and doge attacks on there. A lot of the bosses attacks consist of using the environment, but not always. The final rocket he is hit by is not enough to finish him off, but the lava below him probably is. Hopefully that is the last time you see him.
j capo