Worst boss fight is the Metal Gear Ray fight at the beginning. The Bladewolf is an awesome fight too. Aside from Ray fight every boss fight is great in this.
Love me some humanoid bosses. Mano e mano.
Last boss has grown on me. I was not a fan of the numerous cutscene interruptions in the fight but Armstrong is like a Fist of the North Star villain... cheesy yet awesome at the same time. Now that's a grown ass man.
Forgot Ray. The camera constantly took a shit during that fight for me. I didn't even get how to attack its head for a while cause the headbutt looked like it was charging the laser and I always got out of the way and underneath it.