Wow. That was an amazing episode and the first really memorable gym battle of Unova.

Oshawott did really well and has really become a more durable pokemon. Still surviving 3 attacks until it went down to Palpitoad. And dear god the animation was blissful here.
Snivy's battle with Palpitoed was short, understandably. What was good about this is battle was Clay. It's refreshing to see a gym leader that focuses more on brute force than strategy, berates Ash and best of all, pays the price for his cockiness. I also always love whenever we have a flashback to a characters youth so i can laugh at how they didn't change at all in the past few years.
In terms of animation this was the worst part of the episode, but Clay's character made up for that. Excadrill curbstomped Snivy and tanked Grass it's moves all day. Hopefull she learns Aqua Tail or something so this doesn't happen again. She can't rely on Attract forever.

Roggenrola's battle looked amazing, it felt a bit one-sided until the evolution. I think the only move that Roggenrola got in during the first part of that match was Sandstorm and even that was just to heighten it's defences for the onslaught. The evolution was done very well. The silence before the glow was tense and it was just epic. I really like BW's evolution style compared to previous seasons. And thankfully the animation picked up for this final battle. I do hope Boldore knocking over Ash becomes a running gag. The only bad thing about this is we might not see Ash with his Gigalith unless the anime ignores the trade evo thing. Anyway, Ash wins the badge and we know have Boldore, woop.

This episode really shows that Ash actually has a brain stem in battle and that Gym leaders can be memorable characters. Hopefully the 3 remaining gyms will be as good as this.