Nintendo Treehouse has shown some gameplay of Hyrule Warriors that was not available in the E3 show floor. This demo shows footage of Midna battling hordes of enemies. You are able to do special attacks and magic moves as well which are separated by two meters.
Treasure chests seem to contain items that you can use to access areas and gain new abilities. In this demo Midna gains a hookshot that she uses to get to certain areas and to pull dragons down. Argorok from Legend of Zelda: Twilight Princess appears in the game as a boss.