I've mentioned the concepts of story atoms and game atoms in previous posts, but without taking the time to explain what they are. In theory, an atom of any field of study is an irreducible component. Much as in the physical sciences however, a close examination reveals that atoms are actually made up of even smaller bits.
When it comes to the chemical elements, by the time we understood that atoms were not the smallest unit of matter, the definitions of atoms and the elements were already set, so it's easy to identify when we're dealing with something else.
It's harder in creative endeavors, where you are literally working with the stuff of imagination. When you conclude that the creative atom you've been exploring is really a composite of two smaller elements, do you have two separate atoms, or do you have two units of something else that combine to create an atom? You can't determine it's physical properties to make the judgement. An experienced practitioner will have a good feel for the difference, but as I've noted before, there's plenty of disagreement to be had among experts in every field.
Creative atoms actually come in several types, the more widely inclusive of which verge into a similar concept, patterns. Patterns are well-known, recognizable arrangements of atoms, frequently named to ease communication between creators. The names of the patterns form the core of a descriptive jargon within a creative field.
In the field of storytelling, Joseph Campbell published the best known set of patterns in The Hero with a Thousand Faces. Campbell outlines the Hero's Journey in three broad "Acts", Departure, Initiation, and Return. Each of these is comprised of several optional patterns, such as the Call to Adventure, the Road of Trials, Apotheosis, and Rescue from Without. To anyone who's created stories in any medium or consumed them, these are recognizable patterns used again and again.
In the field of game design, the patterns are little different, but the similarities rapidly become apparent. The best single source for these, in my not-very-humble opinion is Björk and Holopainen's Patterns in Game Design. Their book names and describes over 200 patterns and atoms found in games, such as Aim & Shoot, Privileged Abilities, Imperfect Information, Avatars, Pick-Ups. Like the Acts of the Hero's Journey, there are also Boundary and Structural patterns to games, such as States, Instances, and Sessions.
Most of both kinds of patterns are too large and inclusive to be considered atoms. Atoms are generally much smaller and don't leave much room for confusion. Two examples, one from each of games and stories, illustrate. In stories, a common encounter for the Hero is the Wise Old Woman. The Wise Old Woman is fairly irreducible without losing the essence that you understood implicitly as soon you heard the three words. Remove any one of those words, and the implications of the figure change.
In games, a Pick-Up is a commonly used mechanic, an object that the player takes or captures to replenish or buff their abilities. Again, this is fairly irreducible. You could specify Bullets or Health Packs or Flamethrower, but Pick-Up communicates the intent of the design, whereas any of these literal objects could conceivably be MacGuffins, or Plot Tokens, items that must be acquired to advance the plot but can't actually be used to any advantage.
The main difference between game patterns and atoms and those of stories is one of usage, how their respective grammars are utilized. The grammar of game patterns and atoms is descriptive, while the grammar of story patterns and atoms is expressive. Try discussing the major elements of your favorite story. You'll find that you end up telling the story, just with different words. Then discuss the major elements of your favorite game. You end up describing particular pieces and how they fit together in an interactive experience, but not as a sequence of event.
The fun comes when the two grammars are used in combination. Some games don't tell a story, but many do. Most AAA games have an arching plotline and numerous side plots to entertain the player. A depressingly large number of them make little to no effort to blend the two in a meaningful way, to support the story being told with engaging gameplay that drives immersion in the scene, or to truly build the story into the gameplay elements. Instead it's more common to let the player have some game, reward their success with the next scene in the story, then give them some more game. Rinse & repeat.
But we have been getting steadily better. Studios are hiring writers, writers that can actually craft a story, whereas in the past the job was often relegated to the game designer as the visionary of the game as a whole. The two roles are very different and require different skills and creative sensibilities. I think we can look forward to ever-improving stories in our games, solidly integrated into holistic experiences. And it starts with an understanding of the base elements, the atoms of storytelling and game design.