I already went over why the last two titles were apt, so let's go over this one as well. "Natural Selection" is a bit of an ironic title, as the episode is all about attempted unnatural selection. Mad science created a monster, and mad science created the cure. The process of natural selection is all about the traits most helpful for survival being passed on. Unnatural selection is playing God. The meaning of the title returns when Connors failing experiment proves that he can't play God. He simply can't control the process of natural selection, which, appropriately enough, also states that wounded animals (ones missing a limb, for example) are less likely to survive due to their disadvantage.
The subplot about working at Doc Connors' lab is over. It's kind of disappointing, but it makes sense to me. After all, Peter only took the job at the lab for money, remember? And then he wanted to sell some Spidey pics for money. Basically, this was a three-episode arc about Peter reaching his goal of being able to help provide a source of income for himself and his Aunt, and what he would have to sacrifice to get there.
And yeah, the gene cleanser that Peter swiped will be making an eventual return. Don't you worry.
As for the villain, the Lizard has never been one of my favorite Spider-Man villains. It's a simple Banner/Hulk story with an even more brainless evil counterpart. But I will say this: It works here. This episode gets really personal. With Electro's origin, we saw the transformation and downfall of someone who had no one else in his life. With the Lizard's origin, we see the toll it takes on everyone. There's a lot of really good interpersonal moments between the characters that you just don't see in other Spider-Man cartoons.
And you know what else is a fresh breath of air? The womenfolk are actually involved in the plot as characters. They don't just stand around in the background, occasionally saying a line that could be put in any character's mouth. Yes, I'm looking squarely at you, Man of Action. I know that some of you are getting tired of my continued harping on that point. But I really think this is a problem that must be addressed because it really shouldn't exist in the first place. But yeah, I have no criticisms in that regard this time.
Speaking of the womenfolk, it's also nice to see a version of Aunt May that has a reason for exis....
Okay, look. I'm sorry. Ultimate Spider-Man is hanging over me like the sword of Damocles right now.
Peter Parker is us. The everyman. In this episode, he's less than an inch away from giving up his powers. Willingly. Happily.
Peter: "Easiest decision I ever made."
What other version of the character has had a moment that humanizing? None.
This Peter Parker is a bit greedy. He's a bit smug. He's frustrated. He's depressed. But you know what? He's only human. And we can all see a little bit of ourselves in him as he overcomes his issues and becomes a better person. And that's why this is my favorite Spider-Man show.
Until next time, Excelsior!