This issue isn’t important just because Erik Larsen had the foresight to draw Namor flying around with the X-Men (something the Sub-Mariner wouldn’t regularly do until about twenty years after this was published).
I know that Iron Man is in this picture as well, but lets assume that he has relapsed into alcoholism and stumbled into the frame.
What is most important is that it’s the debut of Steve Ditko’s final marvel creation—Squirrel Girl!
Before she became a nanny/babysitter for Power Man and Jessica Jones, she turned up in this quarterly special.
Ditko introduces the rodent powered hero in a short feature with Iron Man. He’s been kidnapped by Doctor Doom, and the only person he can call for help is Squirrel Girl. The character is just so ridiculous, with her only being able to communicate with squirrels (in 
particularly, her favorite who is named Monkey Joe) and some other squirrely powers. See what I did there?
Early in the story, she’s pleading to be Iron Man’s sidekick, but he keeps blowing her off. The poor girl is clueless. But Squirrel Girl proves her worth when she calls for some backup–Monkey Joe and about a thousand of his little furry friends. They subdue and in turn wind up humiliating Doctor Doom.
She’s a really goofy character and reminds me of Sue Heck from The Middle with her constant cheeriness. The whole thing is just so absurd to the point that you have to imagine that it made Ditko either really mad or he immensely enjoyed the story.
The rest of the book has some fun stuff, involving the X-Men trying to stop a half-human, half-Sentinel who has gone out of control, Namor making making some bird-like friends, and a bunch of Jim Starlin. So should you buy this? Only if you are a speculator waiting for Squirrel Girl: The Movie. No really, it’s a fun anthology and great for some light reading.
Ridiculously Awesome 