Use the following trick to avoid attacks and make your health kits last a little longer when fighting the last Boss. Walk up as close to the posts as possible after hitting them, run a very, very tiny bit to the center of the ring towards the demon, then run back out. The demon will try to bite at you instead of blowing gas at you. Most times, he will bite and miss. Be careful, because after you do this a few times, he will move slightly towards the corner and be able to bite you right through the center of the post -- keep your distance while hitting that post.