In fact, that was the brilliance of the character. It's as if Paul Jenkins (creator of the Sentry) said let's put Superman into the Marvel world but restrain him in every possible way. For those not familiar with the Sentry let me explain. Robert Reynolds is schizophrenic with super powers. As a teenager he drank a stolen formula from a research lab in a desperate attempt at getting high. This gave him the power of one million exploding suns and turned him into the Sentry. Later he would be erased from the memories of everyone in the world including Marvel's superheroes. This was due to his arch-nemesis the Void.
Whenever Robert is the Sentry he is also the Void. The Void is the other half of the Sentry's personality. For whatever good the Sentry does, the Void does evil. Say he saves a bus of 50 people from falling off a cliff; the Void will kill 50 people by sinking a boat. He is the yin to the Sentry's yang, but all contained in one person with far too much power.
The problem with the Sentry is that he's always fighting a battle with the Void and eventually it wears him down giving the Void control. But the potential of the character is awesome. The Sentry was one of Marvel's and comics in general largest retcons (retro-active continuity). Marvel worked him into every aspect of their core titles including: The Fantastic Four, Hulk, The X-Men, the Avengers and even Spider-Man.
The crazy train came to a stop for the Sentry at the end of the Siege, but not until he tore two Gods in half. First it was Ares and then it was Loki. The Sentry had the power of one million exploding suns coursing through his veins, how could he be stopped? He fought the Hulk to a stand still and nearly shattered the earth in two. He brought down Asgard single handily... and had sex with Rouge of the X-Men. He was one of Marvel's most interesting characters not because of his powers or even because of his actions, but because of what he couldn't do.
