I hope you will enjoy your visit to Japan.
The happy man in the left is a editor in chief of the Modelart magazine(https://twitter.com/ModelArtInc). Quiet man in the right is a young modeller/univ student(https://twitter.com/kn20154).
Laughings are mainly their expression of surprise and excitement about precision and fine details they find on the spurues' surfaces, art of partitioning&injection, volume of weapons.... in the end, thay also laughed about they realised that they have to make hopeless effort to put all the sprues back to the box.
For additional info, they indicated that the kit shown is not the final release version. They also stated that the instruction is not yet provided and the kit will be generally availavle in late october in Japan.