Depending on whether you have kids or not, Barney is either the scourge of Western civilization, or a benevolent character that keeps the kids calm and transfixed for short periods of time whenever the big purple dinosaur is on TV. Assuming that few non-parents will be interested in this feature, we'll proceed from the "good Barney" standpoint. That said, "Barney's Great Adventure" completely achieves its goal of entertaining the pre-school set. How it will fare at the box office is uncertain (since matinees seem to be it's only possible attraction), but it should take off once on video.
It's just too bad that the film doesn't even try to entertain the many parents who will "willingly" see the movie with their kids. Unlike animated features that can play to all age groups, this one's got an extremely limited range, and anyone over six or seven will probably find it too immature for them. Anyone even older than that, and without kids, will probably find it close to being an unbearable, if not sadistic means of torture. The bare bones plot -- Barney and the kids have to find an egg -- might keep kids transfixed, but there's not much there to hold an adult's attention span between the moments spent repeatedly looking at one's watch. Even at the mercifully short running time of 75 minutes, it still feels about an hour and a half too long.
Of course if you don't mind big screen renditions of "Twinkle, Twinkle Little Star," "Old McDonald Had A Farm," and "If You're Happy And You Know It, Clap Your Hands," then you might be able to stomach the rest of the material, although the "I Love You, You Love Me" song is about as entertaining as nails down a blackboard. There are also several other more "animated" musical numbers, but while they'll entertain the kids, they aren't the stuff of Disney cartoon lore.
Likewise, there are many moments that kids will giggle over, but parents won't find remotely amusing (Cody falling off a railing into some bushes when he's surprised to see Barney, Barney dressed up like a farm hand, etc...). Even so, there is a fun and imaginative "Willy Wonka" inspired set in Goldfinch's home that should mesmerize most tykes and at least prove interesting for adults to watch.
Despite some restless moments (nearly anytime Barney isn't on the screen for more than a minute or two), there are enough "cameos" from other Barney regulars such as "Baby Bop" that will keep the kids entertained. In addition, the filmmakers have included some moments where the dino characters interact with the kids in the audience (like on the TV show) that elicited the best responses from our audience.
Giving this movie a rating is nearly pointless and difficult to do since its aim is so young and low, and that it doesn't even make the pretense of trying to connect with nearly anyone who's already mastered the skills of multiplying and dividing. Essentially a critic-proof movie, since the target audience is mostly too young to read and couldn't care less what anyone has to say about Barney and his pals, the film succeeds at what it's supposed to do. Young kids will probably rate it a 10 while adults will probably give it a 0 or 1 (not taking into account if they're parents and that it makes their kids happy). Thus we give "Barney's Great Adventure" a diplomatic 5 out of 10 as a balance of entertaining its goal audience mixed with being a near intolerable movie for anyone without kids.