Coincidentally, I'm reading The Walking Dead Compendium that collects issues 1-48. As a result, I've just read the same time frame in the story that is now being presented in the show. The differences between the two are striking, so that the show retains the same feel as the comic, and utilizes the same premise, it goes in a whole other direction.
First, the similarities. Rick is still shot at the beginning, leaving him in a coma when the disaster strikes. It's drawn out a lot more in the show. The comic took all of 1 page to tell that part. Anyway, Rick wakes up to discover there's no one in the hospital, signs of carnage everywhere, and when he opens the wrong barred door, a whole lot of shambling corpses intent on munching on him. As with the comic, Rick first heads to his own house and runs into a man and his son who have taken up residence in his neighbor's abandoned house. They fill Rick in on the disaster and that people have gone to Atlanta to be protected by the military.
It's when Rick gets to Atlanta that there are a lot of differences cropping up. And that didn't even happen until the start of the second episode. Instead of Rick being rescued from a zombie horde by just Glenn, there are a whole contingent of people from the camp on the outskirts of Atlanta who've come in to the city to look for provisions. They're holed up in a department store and are trapped there when Rick's shooting at the zombies attracts more of them. They eventually escape and make it back to the camp.
We've already seen cast changes when in the department store but there are still more of note when we get to camp. We still have Jim, whose entire family was eaten by zombies as he escaped; sisters Amy and Adrea; Dale, whose wife was bitten; Carol and her young daughter, Sophia; and Rick's partner, Shane, along with Rick's wife, Lori, and son, Carl. We also had the aforementioned Glenn. In addition to them are a middle aged black couple, Carol's abusive husband, a young Hispanic couple and their 2 daughters, and a pair of redneck brothers. In fact, one of those brothers was left handcuffed to the department store roof when the others escaped because he's a racist who was trying to take over the group and beat up the middle aged black guy. There may be some other people who I forgot, too. Unfortunately, I can't recall any of the names of these new characters.
After the happy reunion for Rick, he and a bunch of the others go back into Atlanta to try to free the redneck handcuffed to the roof and to recover a bag of guns Rich had brought but dropped when surrounded by the zombies. They're ambushed by a Hispanic group who also want the guns and end up in a standoff with them when each side ends up with a hostage. That's eventually resolved, as well as the redneck not being found because he cut off his own hand to escape. His brother, of course, isn't too happy about that.
While this group is hoofing it back to camp, because the redneck who cut off his hand took the van they came in, a bunch of zombies attack the camp. Carol's husband, Amy and a few others whose names escape me are killed. The camp is saved when the expedition returns in time to re-kill the zombies. Oh yeah, in the meantime, Shane had beaten Carol's husband pretty badly when the husband was being abusive to Carol. This had him laid up in a tent and easy pickings for the zombies.
Like in the comic, Jim is bitten during this attack. After the attack, they decide to leave. Here's where we get into major differences. First, Shane's not dead. In the comic, Carl had killed Shane when Shane tried to kill Rick while they were out hunting. Shane in the show isn't so wedded to the idea of waiting where they are until rescued that it drives him off the deep end, like it did in the comic. Shane still had a relationship with Lori while she thought Rick was dead. Shane's still pissed that Lori dropped him for Rick. Shane lied to Lori about Rick being dead in the show version, which wasn't the case in the comic.
Second, instead of heading out away from Atlanta in hopes of finding some succor, the band heads for the CDC to try to find out what happened. Not all of them go to the CDC, though. The Hispanic family headed to Birmingham to find family they have there. The rest of the band does get to the CDC, where there's one surviving scientist. He gives them the low down that it's some sort of contagion that causes the dead to regain a minimal brain stem activity that drives them to eat whatever living thing they encounter. This is shown really quite neatly with fMRI scans of someone who was bitten and volunteered to be scanned to show the change in brain activity. That fMRI ends with a bullet tracing through the skull after the person becomes a zombie. Of course, it's the scientist's wife.
Which is how we finish at the end. The scientist has given up. His efforts to discover a cure have failed (his wife was by far the smarter one who could possibly have done it), and the CDC is running out of fuel for its generators, which will automatically trigger an explosion that will wipe out the entire building to make sure none of its many other fatal substances, such as ricin, can fall into the wrong hands. He intends to stay there and call it quits. The middle aged black woman in the group decides she can't handle the new reality, either, and stays with him. After much tension and drama about him trapping the others with him for this quick death, he lets them out of the control center, which allows them to break out of the building when Carol reveals she has a hand grenade that she'd found on Rick's clothes at some point.
Third, I don't like how the Andrea character is developing. In the comic, when Amy dies from her bites by the zombies, Andrea immediately shoots her in the head so she won't become a zombie. In the show, Andrea holds vigil over her sister until Amy stirs as a zombie, and only then, afte much weeping and gnashing of teeth, shoots her in the head. Andrea also wants to stay with the scientist to die until Dale says he'll stay with her if she does. These two points in her story on the show make Andrea a much weaker character than she is in the comic. In the comic she's not only the best shot in the group, she knows what needs to be done to save them and does it. In many respects she's the female, more stable version of Rick. The show needs to move her more in that direction and away from the weepiness.
Important missing characters in the show are Allen and his wife, as well as their twin boys. They play a large role in the opening chapters of the comic but don't exist in the show. Allen's eventual death has a heavy effect on Rick, in part because his effort to save Allen not only is a failure but cause Allen a lot of pain in the process. What's more, Andrea and Dale take on the responsibility of raising the twins after their parents' deaths. Unless these characters are introduced later, that's not going to happen.
Here's the thing that I wonder. Has the show taken it too far afield from the comic? The changes in cast aren't that big a deal. The changes made the cast more diverse, which would fit for a cosmopolitan city like Atlanta. But Kirkman has always been adamant that the comic wasn't about how or why the disaster happened. There's been no knowledge beyond what the relatively small cast knows. There's idea what happened in the rest of the US, let alone the rest of the world. And there's nothing at all about how the zombie change works that isn't found out by the survivors by trial and error of trying to save their own who become infected.
I think the way Kirkman has handled it in the comic is better. He's telling stories about these survivors and how they cope. What changes are made in them by the disaster? How do they relate to one another under these circumstances? Do they build in hopes of a future? These are the central elements of the comic.
The show runs the risk of becoming a hunt for how it all happened and what they can do to fix it. I also found the character of the scientist at the CDC to be trite, as well as his whole situation. Holed up in his impregnable bunker, he's had more than adequate food, plenty of water, and so on. He's got it good and doesn't want to continue. Yada, yada, yada. I've seen that sort of thing in sci-fi and fantasy tales innumerable times.
I like the show, but we'll see how it goes from here. If it just leaves the CDC thing behind as a memory, it'll be good. If it becomes a hunt for a cure, it's going to be a whole other thing than the comic. I might still like it, but it'll have a much harder time being the same sort of story about the people that the comic is.
Oh, and Carol on the show is nowhere near as hot as Carol in the comic was. Evidently TV doesn't believe hot women get abused by their husbands.