Character

One of the most important parts of a game is the characters. Without them, most games would not have the means to convey a storyline. First Person characters are characters that the player controls, and third person characters and normally characters that assist the player and help the story pan out. In some games, the choices the player makes may determine the fate of third person characters, such as in Mass Effect, while in others, they just purely assist the player with their quest such as in Guild Wars. A good back story to a character can improve how the player connects with the characters in game, and can vastly improve a game. Another key factor in developing characters is how they come across visually and audibly, especially as how the main character looks can become the main link to the game when it comes to advertising, as they are instantly recognisable, examples being characters such as Mario, Sonic and more recently the Master Chief. These are characters that will last, and people will reference in years to come as notable game characters.
Gameplay
Gameplay is the way in which a player interacts within a game. It is also known as the mechanics of a game, and is the main draw of most games. A game could have the best graphics and audio of its time, but if the gameplay is not good, people will not buy the game. The gameplay should make good use of the environment, such as in Assassins Creed games, you can climb upon buildings and jump from roofs. Players can be rewarded or punished for their actions through changes to the state of the game, such as levels made easier if a player completes other tasks. There are many different types of gameplay, such as Co-op, Linear and Levels. Overall, without good gameplay, most games would not be attractive to players.
Scripting

Without a properly laid out script, games would not flow in a way that is engaging. Three of the main points in a script are the Environment, as in how everything will look and feel. Sound effects and music, which help to create an atmosphere, and thirdly what will happen at that part of the game, such as the decisions the player will be given, and what those decisions will cause to happen. The script will also contain an executive overview of the story, basically a short version of the whole storyline for the game. Also included will be the entire backstory and background of the world the game is set in. There will also be a flowchart which describes how the entire game will play out, how decisions will change the game, and also the quests and subquests in the games. Then there will also need to be a bio for the major characters in the game, and how they interact in cutscenes throughout the game. Finally, cut scenes need to be planned out, and then the storyboard script will be created which, in detail, basically plans out the whole game.