The sequel to Dishonored plays pretty much the same way while giving more freedom in the Chaos department. You’re no longer locked into the chaotic ending after killing a certain number of people, but instead based mainly on who you kill with quantity being very much secondary. There’s also a variety of endings depending on how you resolve the main missions.
It’s meant to be played through at least twice, once as Emily and once as Corvo (and if you want all the achievements, those playthroughs will have a no power/power and high/low Chaos split). You don’t need to have played the prequel or its two DLC to follow what happens here, but those that have will benefit from quite a number of references (the Low Chaos outcomes are canon). For those that haven’t… just be aware that this is primarily a stealth-based game; the melee combat is pretty clunky and you’re not really meant to fight foes directly.
The follow-up, Death of the Outsider, is more like a stand-alone DLC than a proper game. It’s roughly half the size with no collectibles aside from paintings, doesn’t feature a Chaos system, has automatic power upgrades/unlocks, and there are only two endings (wholly determined by your choice in the last mission). While it too treats the non-lethal path through its prequel as canon, oddly enough the lethal ending here comes across as far more natural than the non-lethal one. So while I can certainly recommend buying Dishonored 2 (assuming you like stealth FPP games) I have to suggest skipping Death of the Outsider unless it’s on sale for like $5.