system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] If Superman is so powerful why was Doomsday able to beat him to death?

So ScrewAttack and other fanboys insist Superman is incredibly OP. Why then was Doomsday able to beat him into a bloody pulp. I bought the Death of Superman when I was in 4th grade at the book fair and cried my eyes out because Superman (my fave hero at the time) was wrecked into next new year by this grey monster with ice for a beard. It was fairly traumatic and I want a reason as to why such a thing is possible despite the fact that he seems to be a casual multiverse buster.
gpt
Because Doomsday is just as OP.  

Let's look at Doomsday's background here.  He was created hundreds of thousands of years ago as the ultimate experiment in adaptation and evolution.  Every time he died, he would regenerate with an increased resistance to whatever killed him.  His creator, an alien scientist called Bertron, basically dropped him in the harsh pre-historic Kryptonian wilderness and let him die again and again, for *decades*.  First the environment killed Doomsday, then the wild creatures killed Doomsday, then a lack of food and nutrition killed Doomsday, and he *kept coming back*.  He evolved to not need food or air, he evolved to be extremely tough and vicious, and he evolved to become highly intelligent.  

Then, by chance, Doomsday hitched a ride on a spaceship and started traveling the cosmos.  Now he was facing high-tech weapons such as energy beams, as well as much more powerful opponents such as Darkseid and Green Lanterns.  He adapted and grew strong enough to beat them all.  

Eventually, he ended up pretty much depopulating an entire planet, and the final energy blast that defeated him in that particular battle managed to lay waste to something like a quarter of the planet's surface.  And, of course, that didn't kill him permanently either, it just took him out of commission for a while.  The survivors on that planet shot him into space, and he landed on Earth, where he woke up, much stronger than before again.  

It's worth pointing out that when the survivors of that last battle shot him into space, they shackled him in exceedingly strong chains made of some unknown substance.  He managed to free one arm from the chains and dug himself out from underground, and started beating up everything in his path.  He took out pretty much the entire Justice League, with one hand literally tied behind his back.  The League finally concentrated their energy attacks in one desperate blast, which only served to destroy the chains and free Doomsday's remaining limbs, while leaving him unscathed.  

Let's just think about that for a bit.  Doomsday tanked a combined attack from the entire Justice League, and laughed it off.  

So basically, Doomsday is just as strong as Superman, just as fast, just as durable, just as intelligent, and is not constrained by fatigue, morality, fear, or indecision.  His body is covered by sharp bony protrusions that serve as both offensive weapons and defensive armor, and even if you do get past the bony spines he doesn't have any weak spots on his body to target.  He is the ultimate killing machine, and he can never be permanently destroyed.