@Guardian

I have tried it & it's cool I believe this one also falls under 3D Platform-like, artistic & minimal so there is no need to change the style list.

Castle is just geometrical reference for style proposals. It could have been forest, factory, village, space station... I went for castle theme because it represents indoor design(which is much more style-driven then outdoors) and also because castle can mean lots of things so everyone can use different, original approach in creating it, as everyone did. The proposals were not really about the real, actual game-space but more about the style of that space: realistic, semi-realistic, platform-like, minimal, cartoonish, abstract...

...
I believe that prototype level art-style will be resolved by tonight so that we can, once the number of gameplay ideas is o.k., divide the work & finally start developing the level prototype.