I was a little confused when Arthur Petrelli showed up right when Hiro got the catalyst. He seems to know the exact moment when Hiro gets something and it able to go after it himself or send someone else. Then I remembered that he can see the future and he also got Peter's power. I wonder however why he didn't just get the catalyst from Hiro's mom before she gave it away.
Poor Hiro - lost secret formula, lost Adam, and now lost the catalyst and his ability.

I wonder if at the end Arthur left his own body and entered the body of the soldier.

Terik: I wonder however why he didn't just get the catalyst from Hiro's mom before she gave it away.
I was going to ask that very same thing, but he did send Claire on an errand to talk to Angela. I'm assuming Arthur got the time travel ability from his first encounter with Hiro, so why not permanantly take his ability right then?

The catalyst isn't at all what I expected. I figured it was chemical and Claire was just given an injection. I didn't much care for that little twist but I really liked how Hiro's mother was included.

Nathan saw nothing wrong with giving Marines super-human abilities? Nothing against The Corps, I've worked with Marines for many years, but on average they aren't the most psychologically sound people unless they have several years experience under their belt. They got these guys/gals from Paris Island, where Marine boot camp is, but the guy mentioned doing two tours in Iraq already, so what's he doing there? I suppose he could be a drill instructor but he certainly doesn't act like one. I think anybody could've guessed the ability that injection would give.

In the past I assumed the Haitian's ability worked kind of like Leech's from X-Men, when you're in proximity your powers don't work, now it appears that if somebody is powerful enough, like Arthur, you can eventually overcome this, which sounds like it's more for dramatic effect than consistancy. Also, either the Haitian was still trying to block Arthur's abilities or he was so stunned by Sylar's appearance that Gabe could still use his with no problem.

Speaking of Sylar, he apparently thought it necessary to slice up Elle's head even though he already had her ability. Why didn't she have that overload she did last time he tried to cut her up? Isn't it convenient he always seems to have a short list of people with abilities he can immediatly go after when the hunger strikes him? Evidently Sylar doesn't want to try for the Haitian's ability because he just walked out after taunting Peter.

Daphne was able to run from Kansas to New York at super speed carrying Matt and Ando? That's about as believable as Nathan being able to keep his regular air speed carrying somebody. How can this formula be configured to give a person a precise ability? What would stop somebody from obtaining every ability, if there's a limit?

I guess I was wrong about Arthur inhabitating the body of the marine. That's good because I don't think I could have handled watching another show where Chad Faust plays a character being controlled by someone else.