Are 2D sprites always child-friendly?

For example, the 2D sprites from the SNES game Lufia. http://www.rpg-oase.de/php/index.php?direct+29+Lufia/LufiaMonster1.htm http://www.rpg-oase.de/php/index.php?direct+29+Lufia/LufiaMonster2.htm http://www.rpg-oase.de/php/index.php?direct+29+Lufia/LufiaMonster3.htm http://www.rpg-oase.de/php/index.php?direct+29+Lufia/LufiaMonster4.htm http://www.rpg-oase.de/php/index.php?direct+29+Lufia/LufiaMonster5.htm http://www.rpg-oase.de/php/index.php?direct+29+Lufia/LufiaMonster6.htm ^ Aren't there monsters in Lufia that look scary and could be 18+? What's the difference between 2D and 3D monsters? When toddlers see 2D or 3D images of monsters. What are your experiences?