The main thing I really took away from last night was:
The house is locked up, so obviously Walt has been outed as Heisenberg. You can tell by the graffiti inside that it's common knowledge who he is. Also by Carol's reaction to seeing him. Which of course means by the end of the show someone will turn Walt in. Whether or not that is Hank remains to be seen, but common sense would point to it being Hank.
Walt coming back to visit shows that he has either 1) Faked his death (by using the "cancer"), or 2) Used Saul's "guy" to disappear.
He still has the gun in his trunk, looking brand new (so hasn't used it yet), and he went to get the ricin as well. Perhaps this is a sign that he's going to go out in a blaze of glory, take the ricin then use the gun for something
, who knows. And maybe the ricin will be his backup in case he gets caught. Being high profile as he is now, I don't see him casually breaking bread with anyone and slipping it into their food.
Here's some of Vince Gilligan on last night's episode: