Starter Villian is a novel of "super villains" told in true John Scalzi fashion: it was a lighthearted, campy adventure with a goofy main character thrust into a crazy situation who learned to adapt and survive. All the characters introduced into the story were fun and the novel flowed very quickly from start to finish, while simultaneously painting a fairly clear picture of the world and providing just enough background on some key players that you felt that you knew who they were. 

Could he have provided more background on some of the main supporting characters? Sure. But I don't think that the omission of these backstories hindered the novel's plot at all. 

The only thing that was a miss in my book, was that there were no fricken sharks with fricken laser beams attached to their fricken heads!