Akira Yamaoka is famous for composing the music for the famous video game Silent Hill, including songs such as “Over,” “Devil’s Lyric,” and “For All.” Developers Konami and Team Silent hired Yamaoka to compose music for the video game’s release in 1999. Yamaoka was hired as an employee, because the developers needed to be in control of how Yamaoka went about creating the content. This became more important as they brought him back for sequels, as the game game grew in popularity, to prevent leaks.
Hans Zimmer is most famous for his movie scores, including Mission Impossible, Sherlock Holmes, Gladiator, and Pirates of the Caribbean, just to name a few. He has been an independent contractor for companies such as Silver Pictures, Wigram Productions, and Village Roadshow Pictures. Composers like Zimmer are usually hired as independent contractors for huge film companies. If you have a big enough reputation to grab the attention of major film companies, you should be able to work how you want, where you want, and when you want without the company controlling your every move, provided you provide the desired content, and meet a deadline.