Although typically shuffled in with the rest of Nickelodeon's Nicktoons line-up, Invader ZIM is the odd alien out. It's a drastic change stylistically, favoring darker themes and visuals over the bright, cheery look seen in its TV lead-in, The Fairly-Odd Parents. Invader ZIM sticks with the same hyper-kinetic movement as other kids shows, but tinges it with a smart, slightly absurd sense of humor.
Although there are a few exceptions, each episode revolves around ZIM, an alien conducting a "secret mission" to conquer Earth and Dib, ZIM's classmate and the only person who realizes ZIM is an alien. Both have their own storylines in each episode, although they usually don't overlap as much as your would think. The structure is more of a cat-and-mouse game that only comes together at the very end, similar to Phineas & Ferb.
For example, in "Career Day," ZIM and Dib are paired with working adults after taking a career test. ZIM is sent to work at a Fast Food restaurant, which he believes will help him take over the world - provided, of course, he gets enough promotions. Meanwhile, Dib joins a crackpot Paranormal Investigator. Dib thinks the Investigator will help him finally unmask ZIM as an alien. However, the Investigator is more interested in chasing down a certain cereal-hocking vampire.
Episodes usually last around 12 minutes, but similar to most good British TV shows, seem much longer. Plotlines are simple enough for anyone to follow and shift around enough to keep even kids with super-short attention spans focused. At the same time, the writing is sharp enough to make parents laugh. Some jokes trend towards the juvenile side, but every once in a while an obscure reference will coast right over a kid's head and make older viewers chuckle.
ZIM and Dib's goals are a big part of the show, though episodes are self-contained. Some story elements are mentioned in different episodes, such as "Operation Impending Doom II," the invasion plan ZIM is part of (or, at least thinks he's a part of), though there are not major connective plot threads. In fact, the 14 episodes in Operation Doom are completely out of order, with earlier episodes mentioning items from later episodes on the DVD.
Invader ZIM: Operation Doom offers no extras, but the number of episodes is more than enough for the price. While not a "Best of..." collection or season set, Operation Doom is a great pick-up for fans of the series and a great introduction for newcomers.
