Careful reading Halo 5 comments.

[Torillian]

foodfather said:
Xbox mods on this site are piss poor and lacking, so Halo threads are a no go until I've completed it.

And calling complete BS on tachikoma completing it in 6 hours.

Our writer beat it in 5 hours on normal so I see no reason to distrust Tachi's claim of 6 and a half.