I just played through both and it’s definitely 2. The graphical difference between the two is actually absurd, and the QOL changes, level design, and two main characters pushes it into a separate league from the first. Only thing about 2 that isn’t better is the voice acting. The VA is HORRIBLE in D2 it’s actually kind of distracting. No thanks to Vincent D’onofrio who is an atrocious actor.
Yes for sure. D1 is older but it plays the exact same as D2. The story is a good one and you’ll really enjoy the context you get from the first game when you reach the second. They aren’t incredibly long games so you can finish it in a few evenings if you don’t take your time exploring and doing little side missions.
Two things to keep in mind, since you’ll be playing through D1 for the story, make sure you play through it non-lethally. The low chaos ending is canon so you’ll want to get it so that the plot in D2 makes sense. The other thing is to make sure you play the Knife of Dunwall and Witches of Brigmore Manor DLC (in that order) as they are functionally a prequel to the plot of the second game.