Hm where to start,
Story: Not bad, but 3min is simply to short, if its 20min it would be more fun,
Art: Its good,
Sound: solid
Characters: Good, no need to improve them, but as i said it would be nice if episodes were longer, then characters would show full potential
Enjoyment and overall, good, i give it 7 because due been very very short doesnt deserve better,
Now i watch many anime tv series, but i simply dont like this 3min concept, it is to short, however there is no complex story, there is no complexity at all, its simple,