It wasn't bad. However, I feel it lacks the right amount of humor to carry this sort of scenario.
Proper comedy requires careful consideration. Let me break down at each scene what I thought would have happened to make this funnier:
0:14 - What exactly is this thief's motivation? Seems like he just got started stealing the books, but why has nobody else tried to stop him yet? I'd think this would work better if the thief were an obvious literature-based supervillain of some sort, always cracking book-based puns and intimidating libraries into giving him their books, much like you'd see in an old comic book.
0:44 - As soon as the bookworm finishes his line here, I expected one out of two possible outcomes:
a) They immediately find that all the library's 'resources' have been stolen and the thief is attempting to drag a comically oversized bag of books out the front door.
b) While mired in their books, they finish only to find that not only has the thief already gotten away, but it's also been several days.
Side note: It seems so wrong to me that you drew so many books, and yet almost none of them have any text or pictures on the cover. This is a golden opportunity to fill those covers with all sorts of puns and bad jokes! Embrace it!
1:12 - While low-res explosions are always fun, I really don't think this works as a punchline. Come on! The guy's stealing books, so why not use an example from a famous book to foil him? Get the kid and the bookworm to roleplay a little, and you could reenact Shakespeare or something, then the thief (being the book nut he is) may have little choice but to join in! That's when you get him with a proper punchline that was foreshadowed.
Sorry if it seems like I'm being harsh, but you really are half-way to a great front-pager here! All you need is to up the comedic potential and do some lip-syncing! Take examples from other cartoons here on NG to see how it's done and you will go places!