Broken Base: Is it an awesomely dark take on a popular character, or a collection of mean spirited, upsetting murders of beloved characters? This is the kind of series that splits opinions.
Similarly: is "Deadpool Kills the Marvel Universe Again" necessary or is it a waste?
Catharsis Factor: After seeing Dreadpool kill so many of our favourite characters in both the Marvel universe and the classics, mainstream Deadpool fighting him, breaking him by pointing out how nonsensical his motives are and finally killing him for good is very satisfying.
Crowning Moment of Awesome: Sherlock Holmes of all people defeating Deadpool and than healing the ideaverse by tearing out Deadpool's seed ideas and replacing them with the original.
Fridge Logic: Spider-Man and Thor should have been able to avoid their deaths. The former has a spider sense that should have warned him not to get close enough for Deadpool to shoot him, and the latter should have been able to control the trajectory of Mjolnir to avoid being crushed by it.
Furthermore, even if he had been crushed under it, it's unlikely it would have hit Thor with enough force to kill him. If it had, the planet probably would have been shattered along with him.
Heck, a good portion of the deaths in this series could count as Fridge Logic. How did Dreadpool manage to get into Avengers Mansion, kill Hank Pym, and plant dynamite in the meeting room all without setting off one of Tony's alarms? How did Dreadpool kill the whole of Cosmic Marvel with Galactus, when characters like Eternity and The Living Tribunal outclass him?
Are we supposed to assume Squirrel Girl and Sentry were among those he killed with the Puppets? Because even if you could find another hero to kill a physically, but presumably not mentally resisting Sentry, it wouldn't stick, and Squirrel Girl can wipe the floor with Deadpool and has an army of squirrel friends to protect her if she is mind controlled.
Doctor Doom, Ben Grimm, and Ghost Rider were all killed offscreen. There are also Hulk-like characters like Juggernaut, who have no equivalent to a Bruce Banner form to kill them in.
Iron Man's armor has been shown to withstand nukes, and Ms. Marvel has similarly undefined, but impressive durability, yet a few regular bombs take them out? Same goes for Rogue and Colossus, who are somehow electrocuted to death.
"Dreadpool" apparently has some kind of overdrive setting on his healing factor. By rights, Sue popping his head should have put him down for longer than a few minutes, if not for good, and he shouldn't have been able to put himself back together after the Hulk tore him to bits.
Moral Event Horizon: Dreadpool crosses the line pretty early on and gets worse from there. Taskmaster personally feels that him murdering the Power Pack is the big line crossing moment.
The Woobie: Amazingly, Arcade, whom Dreadpool is forcing to build death traps, is traumatized by what Dreadpool has forced him to do.
Deadpool himself is one in Again.He's been brainwashed by the Red Skull and other villains to slaughter all of the heroes. Due to his brainwashing, he slips into goofy, colorful fantasies whenever he commits his murders, leaving him almost entirely unaware of what he's doing. To make the situation even more heartbreaking, almost all of those fantasies involve him being loved and respected by the same heroes that he's being forced to murder. It gets even worse as time goes on: it's all but stated that part of his mind is aware of what's happening, but is unable to do anything to stop himself.