The kids weren't there to save the world; this wasn't a typical shounen anime. Mostly what they were trying to save wasn't even real...
That's one of the great things about this anime: it brings you into the kid's perspective, where everything seems real or where they hold on too tightly to imaginary things, like Densuke. Because of this, we could be captivated be things that look so real but aren't, the blurring of reality and the virtual world.
I think there were a few things they could have expanded on more, like the Imago thing, but overall one of my favorites.