The player behind the 90′s Godzilla movies was going the Renegade route, killing Shindo because it’s a necessary step in the pathway where you get the spiral beam, which makes the last few bosses a breeze, but either didn’t know or didn’t care that this locked him out of the golden ending route, and thus resulted in the death of Godzilla and all of the potential ally NPCs.
The player behind the 90′s Gamera route wanted the best ending but was so focused on the main questline that he completely neglected every sidequest, and as such failed to unlock the necessary party members (while you get Genbu from the start, Byako, Seiryu, and Suzaku have to be unlocked before the mid-game boss fight with Legion, or else you’ll be locked out of recruiting them AND Suzaku becomes the final boss instead of Gyaos). He ended up using the Mana Blast way too early, and barely managed to beat the final boss. As such, while he did not get the bad ending, he only got the normal ending, which is still a bit of a downer.
The player behind the Rebirth of Mothra series already got the good ending which unlocks the New Game Plus, and beat every single sidequest imaginable, unlocking the super secret power up that allowed them to get the Golden Ending, complete with the difficult but highly rewarding Belvera redemption arc.