The final Boss is large and wields an entire range of weapons at its disposal. The weapons he favors most at first are shooting fireballs and sending out flying and crawling creatures. To defeat this Boss, do not stay on the ground. Notice the two intermittently appearing and disappearing platforms. Jump onto the lower one initially and as it fades, leap to the one that appears above. From here, jump up and take a head shot at the Boss. Head shots are the only way to kill him. As soon as the upper platform fades, leap back to the lower one and just avoid the punishment until you can leap back to the upper platform again. Keep bouncing between the two platforms in this manner to avoid all the ground-based creatures. You will also usually be able to avoid the fireballs and save the time needed to take out the Boss. When the Boss starts to get low on health, he will send out waves of fireballs as opposed to individual ones. Position yourself in a gap as they approach and keep shooting him with head shots until he has been defeated.