Just as I've cleared the first six stages of the game, I've now hit a brick wall, playing against the CHEFBOT-9000. Can't hip-pound it, so I have to throw bombs at its keyhole to stun it. *sigh*
He's not as hard as he seems. You can exploit the small frame of invincibility that getting hit gives you to hip pound his keyhole. Also, before he gets up, you can hit hip pound it three more times to re-stun him. If you have good timing, you can make it so he never gets up again. He was tough, but not nearly as bad as the final boss (jerk took 200+ of my lives).
At most, I lost somewhere along the lines of 400 lives. The 200+ figure was from the bosses last form. The first form is hard, at first. Once you figure it out, it's a lot easier. Wish I could say the same about the last form.
I'll have to try the hip-pound technique to see how it works...