It was a bittersweet ending for Walt. Heisenberg went out with a bang, literally.
It turns out that the unfinished business Walter was talking about in the last episode didn’t involve revenge against Grey Matter like we thought, but he did kill off the nazis and putting ricin in Lydia’s cup (and she ain’t eeeen know it). That last scene of the show was him sitting in his home away from home, the laboratory, as he probably ran through all the memories of all his cooks. One thing is for sure, he was the best at it. The purity of that blue meth was unseen in the streets and went on to hold a legendary status. Maybe that’s why he finally admitted to Skylar that he did it all for himself.
Walt Jr. might hate him, but the scene where he said goodbye to Holli was touching. Then his other son, Jesse, was finally set free. He took a bullet for him and saved him from the automatic trunk chopper of death. The last look Walt gave Jesse was priceless and you knew deep down, that he cared, even if Jesse looked back at him with hatred, confusing and anger. As much as Walt played him throughout the seasons, that fatherly instinct kicked in for the last episode. He wasn’t such a monster after all.
The legacy of Walter White ended a little dramatic, but it was necessary.