First thing's first: do not read further if you haven't seen the last episode of Breaking Bad and you're not in the mood to read a spoiler.
It's all over, and the conclusion, as far as end-of-series episodes goes, wraps up quite a lot of loose ends, if not all of them. Going into the last episode, glass of rye left on the bar counter, all Walt had left to do was figure out how to get the money to his family, as he's always intended. His plan to do this ends up addressing Walt's unfinished business as bit by bit unfolds. There are two parts of the finale: Walt wrapping it up with the people he wants to live, and Walt seeking revenge on the people he wants to die. First up: the living. Now that his son has refused to accept money from him, Walt uses/scares the crap out of his former business partner, Elliott Schwartz, to ensure that the money gets to Walt Jr. anyway, without his son's knowledge. Then, Walt moves on to part two of family closure: Skyler. Skyler, approached by Walt in her small apartment, gets a piece of paper with the location of Hank's body, and, presumably, her freedom from investigative purgatory in the form of a bargaining chip for the feds — meaning she'll get her life back, without Walt. Then, he takes care of the Judgement Day part of the finale: killing who deserves to be killed. While a lot has been said about whether Walt deserves redemption or not, he certainly ends everything very much in control: the people he wishes dead are dead. Those he wants to live, live. Here's a full breakdown of the mercy and destruction:
Gretchen and Elliott Schwartz: In the first sinister scene of the episode, Walt threatens his former friends into providing Walt Jr. with a windfall in 10 months, on his 18th birthday. They, as far as anyone can tell, will get to live and fund the remaining members of Walt's family with the millions left in their living room.
Badger, Skinny Pete: Surprise! Badger and Skinny Pete, Jesse's friends back from way back, was hired as a laser pointer "hitman" by Walt to threaten the Schwartz — they mistook the lasers for sniper rifles, at the encouragement of a series of threats from Walt to make sure they carry through his plan. As Shakespeare Twitter noted, the pair of Jesse's friends were more or less resurfaced as Rosencrantz and Guildenstern. And Rosencrantz and Guildenstern are dead. But not Badger and Skinny Pete, apparently!
Saul Goodman: We're presuming here. Saul is gone to Nebraska, far far away from all of this, hoping to manage a Cinnabon one day. We'll see you in the spinoff, Saul.
Walt's remaining family: Walter White Jr. a.k.a. Flynn, Marie Schrader, and Skyler White (along with Holly) all live, presumably with all but Marie benefitting from the "Schwartz's" windfall donation to Walt Jr. The family, more or less, gets the closure they need from Walt— including the location of Hank's body.
Jesse Pinkman: He's free, after killing his tormenter Todd, and refusing to do his other tormenter, Walt's work. Jesse gets the closest to a "driving off into the sunset" ending of anyone else.
The Neo Nazis: Killed by Walt's machine gun car contraption. The patriarch, Jack, is shot by Walt, after trying to buy more time by promising to reveal the location of Walt's money.
Todd Alquist: The psychopathic neo-Nazi meth cook with a face of gold is strangled by Jesse, with the chains used to shackle Jesse to the lab.
Lydia Rodarte-Quayle: Finally, the ricin finds its home. Walt slips it into her tea, always made just so, by swiping out her stevia for it. At the end of the episode, she has about 24 hours to live as flu-like symptoms set in.
Walter White: This one is obvious. Walt dies, apparently killed by his own contraption, though he was going to die sooner or later anyway. Before he dies, Walt gives Skyler the words she wanted to hear: "I did it for me. I liked it. I was good at it...I was alive," He said, with a similar send-off to Pinkman. He ends it all in the Nazi meth lab, set up to his standards by Todd, and later Jesse. Dead on the floor, grasping a gas mask, Walt is stepped over as the cops sweep the scene, not yet knowing that everything that needs to be done is done.