I haven't played it since I was very young, but IIRC, you picked one of four giant monsters, An alien in a mech, a giant sexy amazon chick, an enormous brain, or a Godzilla wanna-be. You started in a small desert town, destroying everything in your way with an array of powers, eventually graduating to a big city where you could smash skycrapers. Eventually I remember you got to a point where planes would come out of nowhere and drop bombs on you for huge amounts of damage. I never got past that part.
Hmmm....you know, maybe I should get that game out again and write a review for it. --- If you are willing to admit faults, you have one less fault to admit.