It fails at being complete because you have to read through the same story again to create a character and there isn't enough info presented to really even fully build a level 1 character and keep leveling it with the forthcoming rules without a rebuild.
With the old Moldvay boxed set we created dozens of characters (and even got to equip them

) and played through a whole bunch of adventures with a single 64 page softcover book. Now, with 30 years more game design experience the inheritors of this legacy of awesome can't even duplicate, much less surpass that effort.
It's really sad.