His is how to get the navy engineer. First when the first level
starts, go as you would always go. When you meet the guy that says
"come on, we need to get out of here" you follow him. Two, when he
leads you in to the Battleship's post office look around and you
will see a small red wooden box, go over to it [you must have the
skeleton key to open it] open it and it will say you got the navy
engineer. Then beat the level. Congratulations!