Story: K-On! Ura-On! is a selection of short 3 minute extras based on the original series of K-On! Each one had an unique story, one about the cast being stuck on a deserted island, one when they all discuss Mio's panties etc etc. I didn't find these of particular interest, I was glad when they were over. Yet despite this I DID find myself laughing out loud 3 or 4 times throughout this series, it was ok. But the stories are more for a diehard K-On! fan I'd say.
Animation: The most goddamn awful animation I'd ever seen. I just give it a 3 because the use of colour was ok and the majority of the expressions on the characters were sometimes enough to strike amusement themselves into you.
Sadly, the animation, despite all this, was awful. Worst I've ever seen. It looked like it had been drawn by a 8 year old and this did not have a good effect.
Sound: A simple jingle was used throughout this extra, I think it was trying to create the laid-back mood of Lucky Star. But it couldn't quite pull it off. The song I didn't feel suited and it rather annoyed me.
Characters: All the characters in this show were shown to be almost exactly the same- all ditzy, dumb airheads who were very random. Thankfully as the series progressed a few came out of their shells and individual personalities shone through. Ritsu was shown as the cheeky one of the group and Mio as the big-breasted shy girl who gets constantly picked on. Azuya was a funny character throughout. Its just in the first half of these episodes where everyone seemed the same.
Overall: I suppose these episodes are a nice relaxing thing to watch if you have a spare 20-minutes or so and you don't know what to watch, but I can't really see many people finding these of much interest unless they're pretty big K-On! fans.