I worked for INO for 3 years when I was In high school. Great place to work, decent pay for fast food.
But this whole "secret menu" thing is funny. There is no such thing. Basically INO prides itself on customer service and however you order it, they will make it. Certain things have names like animal style (Grilled onions, fried mustard on patty, extra spread, and pickles) or protien style (burger wrapped in lettuce instead of a bun), but there is no hidden menu. It's just order it how you want it. I've seen a guy order a 2 by 16...2 pieces of meat and 16 cheese. Was fuckin disgusting.