Thinking of how to work Guardian Chronicles in conjunction with Fate Core, I had this idea last night that each Chronicle (era) will use a different
Power Level as detailed in the Fate System Toolkit (which I just bought).
The First Chronicle era will use the
Pulp Adventure power level, the Second Chronicle era will use the
Gritty Noir power level (but likely with one or two minor changes), and the Third Chronicle era will use the
Super-Heroic power level but with some additional changes (more skills, a higher skill cap, and a bonus option chart that players roll on to get other benefits [extra refresh, extra stunt, extra stress box, extra aspect, etc.]).
As well, the Third Chronicle will use the concept of Powers from the Venture City Stories world book. The other two chronicles aren't as likely to use those options although certain NPCs (especially Darkstar) in the 2nd C will have powers to make them tougher compared to the PCs.
FYI... after looking more closely at the M&M 3E book I have, I might still come up with some options for running a Guardian Chronicles campaign in M&M 3E, but it won't be my focus (Internet scuttlebutt seems to say that 3E is a better system than 2E). Regardless, from now on, FATE Core will be the default ruleset for GC. (I might try to see how the setting works with the Savage Worlds ruleset, as well.) As well, I'm likely to come up with options for Alternity, although I still need to find a few more of the old Alternity books to make it work.