Al Ewing and Joe Bennett's landmark run on The Immortal Hulk is nearing its end, with three issues remaining in the series at the time of writing. This reimagining of the Hulk mythos, its origins, and what death actually means to the Hulk has introduced whole new powers and concepts to the gamma-powered side of the Marvel Universe.
In many ways, the Hulk is more powerful than he has ever been before thanks to Immortal Hulk. However, he also has new weaknesses he didn't have before, and these are the weaknesses that the Leader and the One-Below-All have been able to exploit in the final stages of this story. Expect spoilers for the Immortal Hulk series.
10 BETTER THAN OTHER HULKS: He Is Completely Unkillable
The first and most significant upgrade to the Hulk mythos comes from the Immortal part of the name. He really is the Immortal Hulk. At first, it would be Bruce Banner killed during the day and resurrected into the Hulk at night, but it has since been changed into a situation where the seems to be no surefire way to kill the Hulk.
Hulk has been dismembered, reduced to a skeletal husk by a satellite solar cannon, and completely evaporated by cosmic energy, but he's still come back every time.
9 WORSE THAN OTHER HULKS: He Is Weakened By The Daylight
At first, Bruce Banner just couldn't turn into the Hulk in daylight or while exposed to UV radiation. Now, it just seems that sunlight weakens the Hulk and interferes with his mental faculties.
Even this seems to have been resolved, as it seems that just the Devil Hulk personality can't come out in daylight. The Savage Hulk and Joe Fixit seem unaffected by the daylight now.
8 BETTER THAN OTHER HULKS: The Devil Hulk Was The Best Of All Worlds
The Devil Hulk really seemed to be the best of all the Hulk personalities. The Devil was intelligent, devious, ruthless, and had complete control over the Hulk's powers. The Devil also had drive and vision and was one of the main driving forces in the Hulk's quest to "destroy the world of humans" (which was really just a mission to overthrow the unjust powers).
The Devil Hulk was also very protective of the other Hulk persona, particularly the childlike Savage Hulk and Bruce Banner himself.
7 WORSE THAN OTHER HULKS: The Hulk Personalities Were Still At War
That said, there still seems to be a tug-of-war between the different Hulk personas, namely the Devil Hulk, the World-Breaker, the Savage Hulk, Joe Fixit, and Bruce Banner. Xemnu the Living Hulk and, later, the Leader was able to set the different personalities against each other.
This isn't new for Bruce, but it wasn't a problem when the World-Breaker was in control. The World-Breaker, mostly active during Greg Pak's Planet Hulk and World-War Hulk and later in Jason Aaron's run on Incredible Hulk, seemed to be a marriage of Banner and Hulk (until the World-Breaker abandoned Banner, and he went insane). It was intelligent, decisive, and only resorted to violence when necessary.
6 BETTER THAN OTHER HULKS: But There Is Some Communication Between Hulks
That said, until the manipulations of Xemnu and the Leader, there was a line of communication and some measure of understanding between the Hulk personalities. The Devil Hulk was mainly in charge, and Joe Fixit, Bruce Banner, and the Savage Hulk seemed to be okay with that.
The main upheaval came when the Leader somehow infiltrated Bruce's mindscape as the World-Breaker Hulk, who seems to have gone missing in the aftermath.
5 WORSE THAN OTHER HULKS: No One Trusts The Immortal Hulk
The Devil Hulk's abrasive personality has alienated the Hulk from just about every other figure in the superhero community. He has fought the Avengers twice since the Devil Hulk took over. The Thing of the Fantastic Four has had a couple of rows with the Immortal Hulk, and Amadeus Cho has expressed his disapproval for Banner's new mission.
Alpha Flight had to commission a special crew of Hulk-busting heroes called Gamma Flight--consisting of Doc Samson in the body of Sasquatch, Puck, Absorbing Man, and Titania--to deal with the Hulk, though they have since come over to the Hulk's side. He still has his allies in Rick Jones, the Harpy, Doctor Charlene McGowan, Jackie McGee, and, most recently, She-Hulk.
4 BETTER THAN OTHER HULKS: He Was Able To Overcome His Cosmic Weakness
The Hulk's one weakness has been cosmic radiation. While the power of gamma has seemed unstoppable in the past, cosmic radiation has been the Hulk's Kryptonite. Henry Gyrich exploited this by siccing the U-Foes on the Hulk, with X-Ray dousing the Hulk with cosmic radiation and killing him yet again.
However, Joe Fixit was able to re-emerge through the Red Door as a green/red Hulk hybrid, and he got immediate and brutal payback on the U-Foes. The Hulk's weakness to cosmic radiation is no more.
3 WORSE THAN OTHER HULKS: The Leader Was Able To Kill A Hulk Personality
The new balance between the Hulk personalities has resulted in an unprecedented occurrence in the Hulk continuity: the death of a Hulk persona. The Leader was able to infiltrate Bruce Banner's mindscape under the guise of the World-Breaker Hulk.
During the ensuing chaos, the Leader exploited the visage of Bruce's father, Brian Banner, to subdue the Savage Hulk and kill the Devil Hulk.
2 BETTER THAN OTHER HULKS: He Can Completely Control His Own Physiology
The Hulk's greatest new ability seems to be his ability to completely control his own physiology. The Hulk has taken on grotesque new shapes and forms, and this is how he was able to unite his body after being reduced to parts.
In visions of possible futures, readers have seen completely new Hulk forms capable of killing all of Earth's heroes and even destroying the cosmic angel, Metatron.
1 WORSE THAN OTHER HULKS: Subject To The One-Below-All
The greatest weakness of the Immortal Hulk is that the One-Below-All, a demonic entity tied to gamma radiation, has taken a more pervasive role in the Hulk's life. The series has retconned the Hulk story by implying that the One-Below-All has been there all along, but it has taken a more active role in the Immortal Hulk era.
The One-Below-All has manipulated the Hulk's deaths and resurrections, made the Leader its herald, and tampered with other gamma-powered individuals such as Rick Jones and Doc Samson. Its end goal is to expand until it becomes one with all reality.