Now this is how you do 100th issue celebrations. Just about every villain from the first 100 issues makes an appearance in one of Jack’s final issues. It’s basically one long, fun fight. And then, at the end, we see this nice “looking ahead” sequence.
Something I haven’t really mentioned before that was (I think) unique to F4 was how nearly every issue started where the last one left. Literally. Like this one starts with the team heading home from their big adventure with The Inhumans in issue #99.
They didn’t do recap pages back then, but part of the Marvel philosphy has always been that every issue could be someone’s first, so every story should be new-reader friendly. Most comics just loaded the first pages with clunky dialog about who each major character was, what essential parts of the current drama needed to be known by a new reader, etc. The FF had this other approach, which was kinda cool.