The manga adaptation has something which fixes the big issues the movie has. Mainly, in the final act, a virus from the MKG components, makes MG go berserk after incapitcating Godzilla. it proceeds to run amok....hmmm wait, haven't seen heard this somewhere before?
Anyways, MG starts to violently torture Godzilla, and the manga is pretty clear this is horrible. MG proceeds to kill Godzilla, straight up, and then Rodan tries to save Godzilla and baby but is horribly killed too.
Like usual, Godzilla is revived from Rodan, but the battle plays out differently. MG is about to murder Baby. And:
Mg keeps fighting, and despite being continually wrecked, keeps getting up! A berserk shell of MG continues attacking. It's final attack is latching onto Godzilla in desperation, and exploding, though Godzilla survives:
I thought the manga had a better idea of how to have an actual villain. Sure Godzilla and Rodan are pests in the first half, but they're clearly just interested in the egg. The way MG is portrayed when it becomes berserk, makes it clearly out to be the final villain. Additionally, the way it fights back against Godzilla after being revived is more interesting than what the movie does.