With "Halo Recruit", Microsoft and 343 Industries have created a Mixed reality experience which offers some interaction and shooting (see video). One of the new "Windows Mixed Reality" headsets is required for the short experience.
In this context, Microsoft makes it clear that "Halo Recruit" is not a real game. You should therefore lower your expectations somewhat. "Halo Recruit" is described as a small and fun arcade experience designed to immerse you in the world of "Halo" to be introduced. Further "Halo" experiences could appear later.
The experience, which is around five minutes long, contains some well-known 'Halo' characters, including the Master Chief and Cortana. The games' weapons and the famous Warthog can also be seen. "Halo: Recruit" will be available as a free download via the Windows Store from 17 October 2017.
Source: Microsoft