I think that it would be good to see more (single-player story structured) games that understand the assets and inconveniences of their form, and use the structure to help develop their themes. For example: If a game has a section that concentrates on frantic deathmatch with rematerialising aliens, this could be the equivalent of a paranoid nightmare dreamt by the character, who thinks that people are out to get her. Minor Half-Life 2 SPOILER: HL2 makes comments on the linearity of the experience and ties this in with the idea of manipulation. A game that is very freeform can reflect this in the themes that it pursues. For example it could examine the concept of freedom. I can't think of many good examples.