Well, here we are. This was the first episode where we saw Ash and Misty battle in the official competition, not just the qualifying rounds. They really showed care and concern for each other in this episode, which I will get to in a minute.
Bayleef's reaction at materializing in Professor Oak's lab instead of with Ash was funny, it showed that she still really cares about him. Ash's opening battle, Totodile vs. Kingdra, was excellent. Kingdra's swirling Hydro Pump looked cool, and seeing Totodile dance in the middle of it was hilarious. And the way Totodile won--by Biting onto Kingdra's snout and letting its Hyrdo Pump build up inside it, was very cool and original. I liked at the end of that battle when Brock said that Totodile probably knew all along they'd win, and that probably helped Ash through the rough parts. Then Misty said, "It helped me through them too." She wasn't even in that battle, so she was worried about Ash. Awww... Anyway, that night scene with Ash asking Misty if she was worried about her battle the next day was really nice too. Speaking of that battle, it was pretty good. It started off really slowly, with Misty and Corsola just standing there while Qwilfish took in all that water. However, Qwilfish getting caught in Corsola's horns after attempting a Take Down a couple turns later was funny, as was Misty's initial "I don't believe this" expression. The way she turned it around in her favor was great though, having Corsola do a close-range Spike Cannon. The episode even acknowledged Corsola's dual-type, when dual-types aren't recognized nearly often enough in the anime, so that was a plus. Nobody mentioned that Qwilfish was also a dual-type, but oh well. Team Rocket's attempts to get close to the Sea Scepter to steal it while still keeping their cover as snack vendors were funny too.
I also thought it was an interesting effect how, at the end when Ash and Misty realized they'd be battling each other, the whole background went black and two spotlights appeared on them, to increase anticipation for the next episode.

A very good episode overall. The battles were a little slower-paced than I would've liked, but I felt the above-mentioned redeeming qualities made up for that at least somewhat. Also raising the score is the fact that for once, Team Rocket actually didn't interfere with "the twerps'" battling. Meowth even commented on it once, saying that it looked like a tough battle.