I'll divide this into 6 categories: Story, World, Soundtrack, Weapons, Activities, and Online.
Story {5/5}: Red Dead has one of the most effortly crafted stories in gaming with fantastic protagonists Arthur Morgan & John Marston, excellent members like Dutch Vanderlinde, Hosea Matthews, Micah Bell, Charles Smith, Sean Maguire, and Josiah Trelawny, and interesting antagonists like Leviticus Cornwall, Catherine Braithwaite, Angelo Bronte, and Jim Milton. Over 100 expertly-created missions and a total of 8 chapters about the fall of outlaws are featured in this game.
World {5/5}: Red Dead has one of the most beautifully dynamic maps ever imagined. Realistic graphics, beautiful lighting, and attention to detail make it stand out. Places like Grizzlies, Valentine, Rhoades, Saint Denis, Guarma, Beaver Hollow, Pronghorn Ranch, Beecher's Hope, Blackwater, and Armadillo are stunning. All kinds of animals roam the lands and you can talk to every citizen you come across.
Soundtrack {5/5}: Red Dead doesn't hold back when it comes to music. At just the right moments, the game can really excite you about what'll happen next. If it wants you to be on the lookout, it'll tell you. If it wants you to feel the dramatic moments it presents you, it'll show you. If it wants you to laugh along with the hilarious ideas Rockstar comes up with, it'll make you. My favorite is when you have to rescue Sean from bountyhunters in Chapter 2.
Weapons {4/5}: When it really wants to, Red Dead can have some massively powered weapons. My favorite is The Carbine Repeater but shotguns, knives, and bows deliver badass kills. Even brawling is dynamic and doesn't always stick to one move like most games. The only problems I have are dynamite having surprisingly little effect in battles and pistols being very underpowered even though dual pistols are alright.
Activities {3/5}: Red Dead has some entertaining activities that The Industrialized Wild West offers. Exploring the endless map, hunting legendary animals, fighting lawmen, discovering sidestories, and talking to members. The problems here are the horrible witness system and there could be more to what you can do.
Online {1/5}: You can apparently do all this exclusive stuff you can't do in Story Mode when it's basically the same stuff. Don't even bother checking it out because the tutorial takes way too long to teach you absolutely nothing. Rockstar never even updates it.
In the end, Red Dead Redemption II is amazing at it's best and downright boring at it's worst but it's usually very impressive. Worth The Buy.