What I missed in this competition is criticism. My app got last place, yet no one lost word a about why. Maybe offer some way to do it anonymously next time. Eg ask them to write a ~1-10 word judgement and publish the most meaningful alongside the results. Even though I expected to be placed in the lower regions the single point dampened my motivation to continue. I think knowing what might need improvement makes this a lot easier in most cases. Personally I would have even preferred "I think its useless" (well it IS to most people) to silence.