Ex Machina/WMG

Hundred's power can affect human hearts.
The mechanism of an automatic pistol is entirely mechanical, and it's the first machine we see Hundred control. Obviously, his power has nothing to do with electricity. He can just control any type of machine, but not living creatures. Fine so far. But consider the heart valves -- an entirely mechanical system that allows blood to flow through the heart one way but squeezes shut to prevent it flowing back. The valves themselves are not biologically complicated and can be replaced by metal equivalents. So if Hundred can jam an automatic pistol with his power, he should be able to jam a natural heart valve too -- which wouldn't instantly kill his target, but wouldn't be too pleasant either.
 * This seems to have been Jossed in the issue where he's on jury duty, where he tries to . Of course, he may have just been going for a placebo effect. Or  . Maybe his power only affects machines... but then again,  might be evidence for this theory as well.
 * Actually, he didn't
 * Possibly, his power is a specialized form of magnetic control, and thus it can't affect heart muscle.
 * Alternatively, the only thing stopping him may be a mental block; he can only control nonliving machines because he thinks that's how it works. This might imply that.
 * ooh
 * When Hundred first gets his powers, he's deafened by hearing all the machines and screams "Shut up!". This causes every machine in New York to shut down. But the man in the boat with him also stops talking...
 * Because he was just told to "shut up!" by a heavily injured man. You'd probably do the same.
 * And at one point he actually flushes a toilet with his powers. No way I can imagine that being electromagnetic.
 * He can stop guns and they aren't electric. It seems to be that he can start any form of mechanism, which is why he can't stop someone from attacking him with a club or bow and arrow, that's a person doing it. If you pull the trigger of a gun, though, the gun is the one that launches the bullet.
 * So, in theory... couldn't the whole universe be considered as one big machine? Is Hundred God?
 * Well, considering the Pope wanting to see him...purging his soul...robot heaven...uh...I think so.
 * This is now not a wild guess.

Crazy Millitary Guy wasn't lying.
The FBI lady seems very shocked when they see him, and the US would try and cover up an incident like his, and what happens to him is very similar to...other cases. Plus how the hell does he get in?
 * I thought everyone assumed this?

Hundred will eventually make contact with the Wildstorm universe.
It was revealed that the technology that transformed him and others came from an alternate universe where the cold war is still going on. The people of that world wanted to prepare another earth for colonization and leave theirs. The guessing portion comes in assuming that they got this multiverse-spanning technology from The Four (The evil Fantastic Four Captain Ersatzs in Planetary and Hundred will eventually travel through the multiverse looking for them and end up in Planetary, where he will meet the Drummer and have a machine banging contest.

Hundred is asexual.
We've never seen evidence of Hundred being sexually attracted to anyone, male or female. There's also a strange rant by a reporter who accuses him of being like the "asexual nerds" who nitpick TV shows. But nerds aren't, generally speaking, asexual - just ask Felicia Day. Or Summer Glau. So using that word must be a clue about what Hundred is actually like. The accident that gave him his powers must have also destroyed his libido.
 * It "must be" a clue about what that reporter thinks Hundred is actually like.
 * His equipment may have been damaged in the explosion.

Hundred is straight, but hasn't found someone he likes enough.
Many engineers find it difficult to find partners they can get along with, especially as there aren't many female counterparts to them. He's just biding his time untill he finds the right lady, and besides, he seems to have devoted 100% of his avalible time to New York.

Brian K. Vaughan can control animals.
During his appearance in the comic he has faintly violet eyes and Mayor Hundred does basically tell him to get out of New York.