It's not a small task, especially if you're the only developer of a (not)game. You have to be the coder, artist, musician, sound designer, writer and likely the beta tester. And learn any software you may need and create a workflow. Basically, take any job you've ever done and multiply it half a dozen times or more.
I disagree.
You can have virtually or truly no soundtrack in your interactive piece (for various, even the most artistic reasons; best example of another medium that done that ages ago would be first person perspective "Lady from the Lake" (1947) with virtually no soundtrack and rarely shown main character (the movie would be likely to inspire FPS genre in video games if only game developers watched anything but movies in their neighbourhood friendly multiplexes)).
You can have virtually no art and animation, who is going to stop you? Hell, you can make characters out of fonts.
You need no writing if you plan on creating a storyless piece.
All in all, in the humble opinion of this boardmember, all that you HAVE to be is 4 of those people (if you consider user interface as artist's job).
Seriously, the only prison of your imagination that exists in this universe is the one which you are willing to create. Sometimes, constantly and endlessly.