2 or 3 stars relative to typical Hulk comics; zero stars for the characters that are actually the main players in it.
Thanos is in this for about 5 seconds, and never does anything interesting or important in it. Most of the story is Pip the Troll talking to himself for the sake of exposition. The long and short of it is this: Pip kidnaps Bruce Banner and delivers him to Annihilus's chief scientist, Doctor Bultar, so they can synthesize some chemical element that occurs momentarily when Banner morphs to Hulk. The Negative Zone villains have no problem controlling Hulk, and are easily successful in their endeavor.
As soon as Pip delivers Banner/Hulk, in exchange for a date with an alien babe that never actually happens, he realizes the consequences he'll face from the Avengers, and sets to spying and trying to return Hulk safely to Earth. This should really be no problem for him with his teleporting powers, but instead he waits and watches until the Big Baddies have extracted the mysterious gamma molecule or whatever and used it to significantly amplify Annihilus's stature and powers. Then, instead of just teleporting the unconscious and captive Hulk, he wakes him up instead, which of course results in a Hulk rampage.
The only purpose of this comic is to watch a mindless Hulk fight a Hulkified Annihilus, which sets up Annihilus's new size, look, and ability to project fear, all of which are seen in the Thanos Revelation trilogy that follows this story.