This was it. "Problem Dog" was the turning point of the season. Don't get me wrong. I had really enjoyed this season of Breaking Bad before this episode, but in a way I feel they were just leading up to this. This was the episode that sets up the remainder of the season and all it promises into motion. Unsurprisingly, it was also my favorite episode of Season Four thus far.

The fall of Gus?
It is so strange not to see Gus supremely on top of his game. However, suddenly he seems in an even more precarious situation than Walt. His meeting "with" the cartel, who didn't even give him the respect of having the higher ups show up for some crudite, was a failure. Gus doesn't want an all out war, but his negotiation tactics aren't going to work this time. Gus showed he can handle himself with Victor's murder, but he generally is a delegator of violence, and that could be an issue if war does break out.
Not only is the cartel after him, but Walt and Jesse are also planning on killing him. That being said, they are also probably the least of Gus' worries. Plus, the DEA is about to come knocking on his door thanks to the stellar work of Hank. Gus killed Victor at least in part for showing up at Gale's and getting seen. Now his fingerprints have shown up in Gale's place and he's in even hotter water than if Victor had been connected to him.
I presume Gus' problems are going to be the focal point of the second half of the season. Even if he's not the main character, everything is revolving around him now.
Ricin
Breaking Bad has done more for ricin than any other show on TV. Pretty much any time Walt or Jesse want to kill somebody, they bust it out. Of course, they have never succeeded in using it yet. Will Jesse be able to get Gus to ingest it? He came close with the coffee, which we later clearly see Gus drinking to drive that point home, and something surreptitious like that is probably the only way they'll ever do it. You can't just shoot a guy like Gus and get away with it. Plus, will Jesse's loyalties end up turning? If not to Gus, then to Mike. Or, perhaps, will it be Mike's loyalties that turn? Or, also perhaps, Walt will end up hiring a hitman, even if he doesn't get Saul's help. It was nice to see Saul again, by the way.
Hank is back in action
Watching Hank early in this season was downright unpleasant at times. As such, conversely it is nice to see how well he's doing now that he's back on Heisenberg's trail. Not only is his mood better, but by the end of the episode he's walking with a cane unassisted. His move with the cup was a shrewd touch, getting one over on Gus is rare, and his presentation was probably my favorite part of the episode. Of course, this puts him right back in harm's way. Gus almost succeeded in having him killed once before, and he had less reason to do so then.
Aaron Paul
Bryan Cranston has been great as usual this season, but at this point he seems like the safest lock for another Emmy. He was excellent in this episode, particularly in his scene at the NA meeting. There's not a better ensemble of actors on television right now. This is an all-time great cast.
Walt's joy ride
If Hank's presentation was my favorite part of the episode, Walt's joy ride in the Challenger was a close second. It was just fun to see him do doughnuts in the parking lot instead of returning it, and when he decided to blow the car up it was even better. I thought they'd call back to the Cousins' exploding that truck last season with this scene, but instead Walt didn't get to walk away unflinchingly while a car blows up behind him. Instead, he sits down and watches it as he calls a taxi. When Walt's in a bad mood, watch out.
Fancy camera moves
I've meant to mention this the past two weeks, but it is apt again so I can do it here. The show has been laying it on a bit thick with the elaborate camera tricks the last three episodes. This episode had a couple of shaky point of view shots, most notably with Jesse's video game fun, and last week had the POV shot from the shovel. The week before had the most gratuitious fancy moves, to the point where I felt it was slightly detrimental. Look, I appreciate good, interesting directing, but sometimes less is more.
Like I said, I feel this was the turning point of the season. I've enjoyed Season Four so far, but I am really excited for what is to come. If things can just continue to be as good as "Problem Dog" was, I'll be plenty satisfied.



One of the reasons that Breaking Bad continues to get better with passing seasons is that while this is still mainly the story of Walter White, its world has expanded so it's as much "about" Gus and Skyler and Jesse and Hank as it is about Walt at this point.
Gus is such a great character because of how remote and mysterious he's been to date. I'm fasciinated to see how he'll react when unable to execute on a seven-moves-ahead chess scheme. *That's* a world that Walt has proven able to to survive and even thrive in (though at a very heavy price of course).
Eric,
That last point you made is a great one. Gus has proven that when given time and space he can outmanuver just about anyone. But it feels like he isnt going to have that luxury this time. As strange as it sounds, Walt might have the upper hand when it comes to pure runnin' and gunnin', going on purely instinct survivalism.