Godzilla: Monster of Monsters was a pretty mediocre game. It was repetitive and ugly. The Godzilla sprite was see through and he didn't so much jump he just sort of levitated, despite that I played the hell out of it when I was a kid. It was the only opportunity I had to take control of the big G and mete out some atomic pain! Looking back on it now one of the thing that really impresses me about it is how it showcases classic non-godzilla kaiju and mechas.
Gezora: Space Amoeba (1970)
Moguera: Mysterians (1959)
Varan: Varan the Unbelievable (1958)
Atragon: Atragon (1963)