Kong could have easily defeated godzilla but the movie makers made him look weak in the movie. Example, how could the battle axe injure godzilla's leg but could not strike his face(that was a death blow by kong). The film makers wanted godzilla to survive. Also kong easily defeated mechagodzilla with the battle axe. I feel they could have taken the fight to hollow earth and that would have been an epic climax. Sorry for the spoilers for those who have not watched the movie. This is just my view. Good movie to watch overall.