There is really not much in the way of similarity in tactics between these two battles. The Battle of the Bulge was, for the Germans, an offensive battle of movement and armor across a huge battlefield. The Battle of Iwo Jima, particularly from the Japanese side, was a battle of small units with no armor (the Japanese had a few tanks, but all were simply put in static positions and used as pill boxes) and very little chance for movement because of the extremely small size of the island. In the Battle of the Bulge, the Germans were on the offensive with a definite strategic goal in mind. On Iwo Jima, the Japanese knew they were doomed and were only trying to hold on to delay the American advance on the home islands for as long as possible.