Cool use of the fixed header/navigation and more interactivity on the sub pages. I can take or leave the dark background but it looks like the product itself is in a black container to it seems a very fitting choice.
Microinteractions
Microinteractions are subtle site animations enhancing engagement. They include triggers, rules, feedback, and sometimes loops/modes. Practical uses: improving engagement, guiding user behavior. Well-designed microinteractions boost user engagement and your online presence.
i am subzero website is awesome, try the product its even better!