yeah the 15 second limit is kinda just a guide you can make it as long as you like, it just makes sense to have a guide that is doable in a month.
the idea behind these is an animation exercise rather than telling a story, you can kinda hint at a bigger story but the idea is to limit animators as we have a tendancy to want to make epics everytime a new project is started. to get what i mean watch disneys tarzan the bit where he first sees jane and he puts his hand to hers. theres a whole load of back story you can get from just that bit. admitittedly that was all glen keane but thats what to aim for if you want a story in it.

