They don't look 'cool' enough. They look far too colourful. As realistically drawn people it doesn't really work. It's like they want to be cartoony but aren't. This would make it difficult to put them into a game imho. You either have them more cartoony and put them in a happy-fun Nintendo style game or you make them darker and more gritty for a more mature game.

Such are the limitations of using humans in games imho.