Well, he lost me when he started talking about a 5 million dollar home going up in a few weeks. We have plenty of McMansions in the Detroit burbs, and they went up fast, not a few weeks, but a few months. And let me say this, you could not give me one of these homes. Mortar crumbling, roofs leaking, foundation problems, shoddy drywall, electrical, HVAC problems, etc... The shoddiest workmanship you would ever imagine, and these were near million dollar homes when purchased new around ten years ago. But they were in a hurry to get em up!
If I had that kind of money for a game room, much less a house, I would be on site every morning and have not just a foreman, but my own foreman to run the job right next to the GC. And I would want him to be a royal pain in the ass when it comes to workmanship and overall quality of the build. Along with the architect and an engineer at my beck and call for regular inspections, man I would be ANAL!
As far as the game room, call in a pro. You install windows, have the window company do it. Install a shower door, have the guys that install shower doors for a living do it. The flooring, hire a floor man that eats and breaths the stuff. And no sub-contractors. I hire you, I expect you to be their, not Joe's handyman service.
Now, if any of this is for real... But I know what I would do, and my house would not be up and finished in a few weeks. It took me longer than a few weeks to build my garage, but it is done right.