Specifically, 99% of them are exactly the same story, with exactly the same character, and it becomes 72 pages of mostly-indistinguishable sameness.
Indeed, the most homogeneous element is the hero of these tales, cookie cutter "explorers" or "space patrol" officers, bland bland bland bland bland.
They even go so far as to essentially have the same name. Borrowing from Flash Gordon and Buck Rogers, they all have the one syllable (exciting) nickname and two syllable last name.
Take, for example, Planet Comics #9 (1940), which features these fine fellows:
Flint! Crash! Buzz!! Oh, if only the stories they appeared in were as exciting as the names.
Oh, wait, I forgot one:
SPURT!?! Your hero is named SPURT?!?
Considering that the lead story in this issue was "Invasion From Uranus" (no, it wasn't a Spurt story), this issue must have had the youth of 1940 giggling like Beavis and Butthead...