Little Rocket ManG 30

To unlock this achievement you must pick up the Gnome at the start of the game and carry him throughout the game until you reach the White Forest Rocket Silo, where you will place him inside a hatch on the rocket launching him into space.

Note: You must close the hatch door after placing the Gnome inside the compartment for the achievement to unlock. The Gnome can be found in the communication shack at the beginning of the game on the floor.