I really had no clue who most of the characters were yet, but that was part of the fun. Beautiful Don Newton artwork that really didn't look like anything I'd seen up to that point. I thought Arsenal was a pretty scary bad guy at the time. As I recall, his origin was tied into Avengers backstory one way or another, but that didn't stop me from digging it.
This one featured George Perez and Terry Austin instead of Byrne and Austin, which I barely noticed at the time. The cheesy melodrama grabbed me when I was young, and the Frank Miller/Terry Austin cover gave me a charge. I always loved depictions of Cyclops in action.
Another one that relied on a lot of backstory. Franklin Richards and Agatha Harkness, and Franklin's latent powers...stuff I knew nothing about, but, as usual, those elements gave it an air of mystery that grabbed me. I remember this one being pretty creepy, but I haven't read it in years. One thing I do recall is Pablo Marcos inking George Perez...always gave Perez's pencils a unique look.
This was a two-part story that introduced me to the modern Dr. Octopus/Spider-Man dynamic (previously my only exposure had been in Silver Age reprints of the classic Lee/Ditko stories). Some cool imagery that I can still recall, like Doc Ock being pulled underwater when his tentacles got stuck in a submarine hatch.
Or something like that.