Here the interesting blog in japanese, abuout the history of the investiments and describe the interlink with the below road that pass inside the tunnel.
We coud not take the elevator tothe topfloor bar. It was crowded, many visitors. Despite that, we ate in a good oriental caffe, adn admire the interior of the main entrance.
There are an Hotel, a Residential part and a Hal part with some venues, I do not know how many and how big yet.
Here a video from the main entrance trhough the Garden pathway.
More pictures in the gallery below. Some pictures are from the annex, which is a 3 storeys restaurant, kaiser from paris I guess.