First of all, the book is not flawed in any physical way. The printing is great, the binding is great, and the color is great.
What's flawed are some of the stories. But the flaws are fascinating! For instance, in a story about going to the moon written the decade before it actually happened, we have a man, in a space suit, granted, falling back to earth through space and merely floating to the ground with a parachute. Nevermind the whole tendency to catch on fire when entering the earth's atmosphere at several hundred miles an hour.
Fabulous! I mean it. Far from being a negative thing, such a flaw really points up the refusal of writers like Feldstein to let ignorance get in the way of a good story. It's great to see him stretch a plot to make way for an effect, too. Like introducing a character called "peach pit" (because he likes to suck on peach pits of course) in order to allow for an alien seed to get into his body to be "born" in a way that anticipates Alien, once again, by decades. You would think the government would be pretty careful with such life-threatening cosmic nuts, wouldn't you? Well, I won't spoil the ending. Hilarious!
Even the flaws reveal Feldstein's wonderfully playful talent for either making up altogether or finding stories like these and adapting them to comics. He was so unafraid! For instance, what do you do with a multi-dimensional creature that appears only partially as a floating blob in the air? You theorize about it a bit before harpooning the thing and tying it to a couple of trees with some good, stout rope, that's what you do! And why? To destroy it of course. After all, it's already made the neighbor's cow go poof! That's humanity in a nutshell.
These comics are a monument to the power of the imagination to do the best it can with whatever it has to work with in order to have a little fun (or to defend the planet, presumably . . . without all the red tape). Even the flaws are fantastic!