There are three basic jobs that you need to make a game:
- Writer: Excels at the 'scenario writing' phase of developing a game.
- Designer: Excels at the 'character design' phase of developing a game.
- Sound Engineer: Excels at the 'soundtrack' phase of developing a game.
Directors and Producers are more well-rounded individuals that can accomplish the above tasks. When assigning someone to the phases of the game, you'll get better results assigning someone with a proper title and slightly lower stats than you will if you assign someone with high stats and a title such as 'hacker'.
Coders exist to help you along the road to completion of the game faster. Hackers are the advanced version of coders. It's good to have one or two coders on your team, but when it comes to hackers you should almost always use a job change manual to change them to another job title. Their stats will go down if you change their job (to a writer, for example), but they will start off with higher stats than other candidates for that new job and leveling them will increase that number further.
Hardware Engineers exist for allowing you to create a console. They contribute to completion of the console and games as well.