I've seen some of the old Go Nagai drawings of Mazinger and this is a very different style. That Mazinger in the top part of the page looks more chibi(?) than anything to me. Mr. Nagai drew Mazinger in a very elongated fashion and you've shortened him.
The cheesy dialogue is pretty much on point but you've cut the action way too much. I'm guessing you did this to keep it down to one page but Koji yells "breast fire" and we don't see anything happen. Where's the breast fire?! Even in the old comics Mr. Nagai liked to show the breast fire and the beasts melting away. You still had room for some action on the page instead of filling it up with whatever that mass is and the explosion in the last panel.
Of course, this is just my opinion from one Mazinger fan to another. You may do with it as you please.