Overall, the story line is excellent. The group of young teens (plus one "animal", as it says in the opening) get stranded on an uninhabited planet. The main premise is an old one: characters get stranded, must learn how to survive, get along, deal with assorted trials of nature and bad guys, figure out how to get back home. But for once, the writers handle it all very well. Episode plots are tight, the story moves along briskly but without sloppiness. One story arc lasts too long, which made the next one feel far too short, but other than that, the writing is as good as that in any top series.
A lot of thought went into real elements of survival in the wild, and the kids definitely have a hard time of it before they learn how to do all the necessary tasks to feed and shelter themselves. It's not a picnic at all, contrary to most shows, live action or animated. The characters themselves start out as cardboard cutout stereotypes, but eventually individually-focused episodes and a bit of back-story flesh them out enough that you can't help but root for them all. The writers maintain a good group dynamic throughout the series, with different characters revealing strengths and weaknesses along the way.
Also, Chako is quite simply the best cute animal mascot character in any series, ever. And I absolutely hate cute animal mascots (except Teto from Nausicaä). I hate them in anime, and I hate them in Engineering in the new Star Trek movie. But Chako is a good one.
The artwork isn't all that great, but it's not meant to be. The characters and animals all have a Pokemon look to them, but it's not objectionable. The backgrounds, landscapes, and alien designs are well done, with nice colors, giving the viewer a good feel for the planet and its creatures. As others have mentioned, the character artwork and animation is very inconsistent. It seems like some of the in-betweens just weren't done as well as the key frames. There are also a few moments where you want to shout at the screen to tell the animator not to attempt to do certain camera angles if he can't draw those perspectives. But overall the artwork is nice and colorful enough, with that Pokemon-like bright and cheerful look, while still having a different enough to have its own character.
The opening sequence music really sets the mood, and reminds me of 80s American TV for some reason. End music is decent enough, but not as good. Background music is pretty good, and mostly unobtrusive (as it should be).
I'll miss this show now that I've seen the whole thing. Disney would make a fortune licensing it for the US market, and I don't understand why they haven't brought it over already.
