In this paper, we describe and discuss interaction techniques and interfaces enabled by immaterial displays. Dual-sided projection allows casual face-to-face interaction between users, with computer-generated imagery in-between them. The immaterial display imposes minimal restrictions to the movements or communication of the users.As an example of these novel possibilities, we provide a detailed description of our Consigalo gaming system, which creates an enhanced gaming experience featuring sporadic and unencumbered interaction. Consigalo utilizes a robust 3D tracking system, which supports multiple simultaneous users on either side of the projection surface. Users manipulate graphics that are floating in mid-air with natural gestures. We have also added a responsive and adaptive sound track to further immerse the users in the interactive experience. We describe the technology used in the system, the innovative aspects compared to previous largescreen gaming systems, the gameplay and our lessons learned from designing and implementing the interactions, visuals and the auditory feedback.