Simple, clean and white. I like that. The initial idea with the box is very good but could have been realized more consistent.
On the second page the text on the actual is not clickable and it took me too long to find the "enter" button. Either make the box smaller or the button bigger. You are kind of suggesting a function which is not there.
Same on the third page. Make the box work, make it clickable. The navigaton cross on the top right is not clearly perceptible as the main navigation.
No harm, but this great idea seems not fully reallized.
One small last thing. When navigating though the site the black box rotated on every navigation click you make. The text on top of it not allways ends in the same position. There are combinations of navigations paths where the toptext magically rotates 90 degrees before the box starts to spin.