Here's my own thoughts first:
#1, really like the color of the fire. Wish I could figure out how to replicate it. I'm not sure I really like the angle, but I'm not sure it's any better when I straighten the horizon.
#3 I like the closer crop and the selective desaturation. I wish I could have left the color of the flame in the lenses of his goggles, but alas, it looked too weird.
#4 Cool, but cheesy a the same time.
#5 Raaaaaar!
#6-7 I could do without the red "ghosting" near his face.
#8 Again, I like the close crop. I know that flash shadows are undesirable, but I think it adds to the form and shape of his pose.
#9 I really like how the flames are more subtle here.
Overall, I wish we weren't in his back yard. The grill, the trash cans, the plants and even the lights are distracting. But this was my first experience shooting anything like this. First time "dragging" the shutter too. I got a lot of cool images.