The term 'Game Developer' covers a whole lot of people, people that do a broad array of jobs, and have wide-ranging skills. Any given company may have varied requirements that are pre-requisites for any of their different job titles. On top of that, roles and requirements may change depending on how large a company it is, or even how large a team. Small companies may require an individual to be skilled in many different areas, whereas larger companies are often looking for specialists with deep knowledge in their particular expertise.
These are the people who make the games look and sound good, and this is generally the largest team (the team with the most individual members). This area also has many different professions within the term of 'Artist'. But 'Art' is broader than merely the visual arts. 'Content' includes Sound FX, Music, Voice-acting, Motion Capture, and more.
Someone has to make the games work, and those people are the 'Coders', or 'Programmers'. Either working with an existing game engine, or creating one from scratch they put all the pieces together and make a working game.