Game series with flawless records

[Veknoid_Outcast]

Wright said:

We need to find some consensual criteria of what qualifies "flawless", because I see people posting franchises that I hardly qualify as "flawless". I know it's opinions at the end of the day, but I really think this thread would benefit of us getting some kind standard together (?).

Fair point. For me, it means without any significant blemishes. So, I would ask myself: is every game in the franchise worth playing? Would I recommend every game to others? If I were to submit a report card, would it be all As and Bs? Or would there be a rogue C or D in there? Are there any games in the series that diminish it overall?