Ok, in the description for manyshot it states that the first attack fires 2 arrows. If you hit both arrows hit. However I am unclear on the next part. Apply precision based damage (such as sneak attack) and critical hit damage only once for this attack. What does this mean?
It means for example, that you don't get to apply things like Sneak Attack more than once. Or crit multiplier.
Let's say you shoot 2 arrows using Manyshot, and you roll a natural 20. If you have +1d6 Sneak Attack, you don't get to use that for both arrows, and you don't get the multiply the second arrow for the crit either.
edit: ninja'd!