Yea, it woulda been wise to mess around more with the weapons. I'll go ahead and make another video to fix my mistake with Tengu Man. Besides, I played like a COMPLETE idiot against Tengu himself so it'll be good to get my revenge.
If you're looking for another challenge, you can try to beat Airman's stage as a pacifist without using E-tanks. I was able to get it so that I only use 1.... but I couldn't even get that on Camera.