Level 25: Jump up to the middle of the room before he starts moving and get the
power to breath fire. The easiest way to defeat him is to stand on
the highest platform and shoot him on his highest jumps. You will
only have to dodge when he tries to jump underneath you.
Level 50: Like before, gather the powerup before he starts moving. Learn the
pattern of his movement and attacks before trying to shoot him.
Level 75: Again, get the power up quickly. Stay on the level that hangs about
where his head is when he jumps. Shoot at him when his head is your
level. Watch out for the fireballs he throws, but once you learn his
pattern they get easier to dodge.
Level 100: The final boss. The powerup in this stage works a little differently.
You gain the ability to shoot lightning bubbles which need to be
popped in order to be effective. I recommend climbing up the
platforms while the boss has his back turned to you. Then jump toward
the wall and press the attack button as fast as you can. As you move
down the wall, you will fire a steady stream of lightning bolts at
the boss. These bolts will also destroy the projectiles he throws at
you. Don't stand in the corners too long or you could get nailed.
Like the bosses before, once you learn his patterns he shouldn't be a
problem.
Note: After defeating the final boss, you will receive a password
which will start you over at level 1 with harder enemies. The
bosses will need more hits to defeat, but their patterns remain
the same.