To answer your question, no 96 MILL doesn't require Steam.
It uses HTML5 technology and runs in your web browser on Windows, OSX, iPad, Android, Surface, toaster (if it has a decent web browser)
It requires no download/install process, and updates automatically.
We're currently pursuing a steam release with our publisher,
we'll let GB know when that goes live.
Thanks! and let me know if I can answer any other questions