>Sky turned around and fired his weapon at the small black creature, destroying it

That's.. kind of overpowered. Even Sora with the keyblade couldn't one shot a Shadow. Imagine it this way, our characters are basically at level 1. Quite like Sora at the start of each game, we can't just easily kill Shadows. I like to believe that I have shown this in the opening post with the statement of:

>Gail was up on her feet before the Shadows had noticed it and managed to punch one as it was falling towards the group. Two Shadows moved as one to attack Gail as the one she punched stood back up and grappled onto her.

Even Gail, with all her memories(though not all of her strength), was unable to kill a Heartless in one shot.