Since videogame narrative is still (mainly) taking its cues from its bigger brother, cinema, a lot of stories are built around the same techniques as a movie scenario. Thus, it is common to hear game directors or creators using the lexicon of the seventh art. I observed a trend over the last few months of game directors discussing the elements of their works and justifying them through the concept of theme.
A theme, much like in cinema, is the idea, or message, underlying the work, presented through motifs such as characters and their actions, sets, color schemes, dialogues, etc. Even the smallest detail can draw from (and to) the theme. Some of the grandest works of art had a theme and incorporated it cleverly, creating some sort of interaction, whereas symbols and references create a network of signification that adds to the effect the work has on the viewing public.
Now, games can, and do, have themes. For example, Bioshock is a game about power and manipulation, and the many enemies citing the Bible seconds before attacking the player is a reference to religion, one of many references to a form of power and manipulation the game contains. Games being an interactive medium, they can incorporate themes in their mechanics in ways cinema cannot. A game mechanic can be modified to add an echo to what the game is about, and this can be done seamlessly, or it can be forced upon the player.
