High chaos playthrough now finished, and there are two possible endings on the high chaos playthrough, which makes three endings in total.
ZOMG Spoiler! Click here to view!
For the two endings in high chaos it's literally the very last thing you do in the game that decides which you get, so it's dead easy to go back to a save and see the other one. Basically if you don't save Emily from Havelock you get the really dark ending where the entire kingdom is fucked, it succumbs to the plague and infighting, and the narrator says it's probably for the best. If you do save Emily it's not quite so dark, but everything's still a bit fucked really, because of the path of terror and violence that Corvo took to achieve his goals.
I was really impressed with the differences on the low and high chaos playthroughs, which became increasingly more pointed towards the end. Yeah in fairness the majority of the game plays out the same but you can't reasonably expect them to effectively make two games and then bundle them up into one.
ZOMG Spoiler! Click here to view!
The real shocker was Samuel properly turning on me as he took me to the final level, to the extent that he deliberately reveals you to the enemies. That was a go back to a save and sleep dart him job, I just couldn't bring myself to kill him.
The last level I made an absolutely glorious rampage of, because I'd maxed out on runes and got loooooads of cash, I had a 100% pimped out weapons arsenal with all the blueprints, along with all the death abilities from the runes table - which allowed me to play the last level pretty much as a total carnage-fest (blinking around like bastard to use the high ground, and then just crossbolting or shooting or death-dropping at my leisure, there was even a lot of straight up sword fighting in there). Crude? Yes. Satisfying? Yes. Reducing the game to a borderline-FPS felt a bit cheap but oh my god the slaughter was so cathartic.
ZOMG Spoiler! Click here to view!
Getting to finish off Martin and Pendleton yourself in high chaos is far better IMO than just having Havelock kill them before you even get there. Pendleton you find cornered in a little bolt hole, if you kill his guard and wait for his speech to pan out, he just dies of his wounds for a 'neutralised' result. So I went back to my quicksave and crossbolted him right in the eye before he finished yapping, and for extra fun then removed the crossbolt that killed him from his face.
45 hours playtime and I don't think there's been a wasted minute in the entire enterprise.
I'd genuinely elevate this game to the ranks of one of the best games I've ever played. Pure delight.