The most complex thing I put together in Construct was an incomplete Action RPG concept called Thousand Islands. You adventured around radomly-generated islands, killing bad guys and picking up treasure. There were bosses, equipment, and special skills. It was no Diablo 3, but maybe a Diablo 0.5.
I'll be using the things I learned in Construct 2 to take Thousand Islands out of a concept and into something more. Until then, if you want to play what I had put together I put a copy of the last version online right here.