Long-time web users will likely remember the Flash website intro craze of the early 2000s. That era came to an end for a variety of reasons, including security risks, browser compatibility, and the sheer impracticality of a long intro sequence in a world of growing impatience. These days I would never advise the use of Flash in any capacity—much less as the backbone of a website.
However, I actually went with a similar concept in my design choice for the Merrill X website. The intro/teaser is built on HTML5 rather than Flash, but it’s certainly reminiscent of that old technology.
I mainly just wanted to get something up and running quickly, and for the few people who visit the site directly, I think it provides a solid rundown of what we do and how to get in touch.