The Outsider has bestowed his mark on a few people over the centuries — Corvo, Daud, Delilah, the Lonely Rat Boy, Granny Rags, and now Emily, to name but a six — and while there's a sort of common thread running through the powers they get (rats; darkness; arkane whisperings) they do tend to manifest slightly different ones, on a case by case basis. In Dishonored 2 you get to choose between playing as Empress Emily Kaldwin, the daughter of the previous, abruptly murdered Empress, and therefore born great, or Corvo Attano, gruff and somewhat unwilling assassin who had greatness thrust upon him as the protagonist of the last game.
Based on the hands on time I got with Dishonored 2, this choice is going to affect your game a lot. Corvo and Emily's dialogue with other characters is obviously different (and that dialogue and the potential game endings will both depend on decisions the player makes as they go), but the gulf between Emily and Corvo's abilities, and how that switches up your play style, is surprisingly wide.
I went through the preview level as both of them, and they each had three supernatural abilities unlocked. Corvo had the area-of-effect knockback Windblast, the ever-popular Bend Time, and staple teleport move Blink. They're all moves he had in the original, and playing as him again felt like putting on an old coat. It's an appropriate feeling, because Corvo is sort of doing the same. After fifteen years of relative peace he's having to slip back into the role of assassin, and it's to depose an usurper to the throne again, too. That's some very specific deja vu. He's older, wiser, maybe starting to get a little tired, and consequently his skillset seems to lend itself to a more precise, considered approach. Corvo looks through walls to check the path ahead before he steps onto it. With Bend Time he can approach situations at a leisurely place; he can even leave that situation behind and go to do something else entirely, if he wants to. I'd hesitate to call it easier, but there's certainly less fuss, if you want it that way. As Corvo I found myself wandering about in the open a lot more, because it was simpler to get out of trouble if I was spotted. Not that Corvo is at all an unprofessional assassin, but I imagined he was running on a combination of being quietly confident and not being arsed with all that crawling about stuff these days.
His daughter is quite the contrast. Emily, unlike Corvo, is new to the whole 'cryptic men bestowing otherworldly powers on you for his own amusement' so it feels a little like she's still learning. As Emily I had access to Domino, which chained whatever happened to one enemy to any he was linked to; Shadow Walk, which turns Emily into a nebulous cloud of darkness crawling across the floor at some speed; and Far Reach, her traversal ability that's kind of similar to Blink. Except it's not. Far Reach is basically a slingshot, and Emily keeps moving after the fact. She stays solid and visible while she's Far Reaching, which means she'll crash into anything in her path (which, to pick a random example that isn't necessarily related to my own fumbling attempts to master her powers, could include light fixtures or various ornamental display cases). She can also used it to violently grab and pull objects and enemies back towards herself.
Emily feels more about keeping momentum up — about escape and obfuscation when you are caught, rather than not being caught at all. Even Shadow Walk doesn't actually make you invisible at lower levels, it just causes guards to balk at the sentient child of an unholy smoke machine that crawled under their feet. Combined with Domino, and other powers we've seen including the ability to create a double of herself using Doppelganger, Emily feels less precision and more style, which is fine for an Empress because someone else will clean up afterwards anyway. She might take longer to get used to, but Emily is who I can see people using for the really creative kills, or impossible speedrunning videos.
Their personalities are emphasised by the addition of voice acting, to give you insight into what they're actually thinking, but it was fantastic seeing the differences between them are more than superficial. The way Emily and Corvo's personalities bleed out into your game makes me happy to go on record now and say Dishonored 2 is going to be worth several replays.