It's because the prototype was released this week. Wait Sunday, and it'll be on site.
Unless you have a release date, this game had no reason to be on 3DSL yet. But the prototype is a good reason.
A thought just occured to me. It might be helpful to have a list a of titles (in a thread) that are known to be in development, yet have no rightful place on the main pages yet.
I'm thinking of making a forum section for upcoming games so visitors can post infos and discuss them there then when they have nearing release date, an updater can easily add an entry with these infos.