Where to start?
Story Mode -
Red Dead Redemption 2 is a prequel to the 2010 game Red Dead Redemption, but in many aspects, it outshines its predecessor. RDR2 improves on everything RDR1 already had, and it brings many new mechanics to the table. Hunting is now necessary, not only to obtain pelts for crafting clothes and satchels, but to obtain meat, to cook, and eat, which brings me to my next point, which is eating. Arthur Morgan, the protagonist, has 3 cores, which refill when you eat, drink and smoke. These cores determine how fast your health, stamina and dead eye regenerate, and keeping them full just feels necessary. The atmosphere of the game is phenomenal, with the vibrant game world, and the fact that the npcs are more than just npcs. With its beautiful soundtrack, and engrossing story, RDR2 deserves to go down in history as one of the greatest games ever, even going beyond The Witcher 3.
Red Dead Online -
Red Dead Online is a mess, and a stain to the franchise. It's sloppy, and filled with glitches and bugs, to the point of which I stopped playing for a while. When first released, it had almost zero content, but now it has its fair share of content. Their are five roles, of which you have to buy with gold bars, RDO's premium currency. In my opinion, Rockstar should have used one currency in game, instead of introducing a premium currency. By doing so, they allowed themselves to promote their gold bars every time you log on. RDO is a watered down version of story mode, without the gorgeous story, and with grievers, glitches and the inevitable "could not connect to Rockstar game services at this time" screen.