The enemies on this stage are better armed. As you begin running through the stage, you will encounter a foot soldier equipped with a shoulder mounted bazooka right around the same time a gunner appears from the left. Take them out, and climb up the ladder to take out the supply runner. Stick to this level, and occasionally climb up to the top level when you are being followed by gunners. They will climb up after you and you can easily remove them before continuing. The building will end and you will reach some crates. Stay off the ground when the crates end, as a combat specialist will rush you, and another will parachute down from the sky, for a deadly combination.
You will continue to run through more crates, and eventually another building will appear. During this time, you will face many more bazooka tooting foot soldiers. A supply runner is typically located quite close by. Use the ladders to make the gunners, bazooka soldiers, and supply runners come to you and make them an easy target. It's not a bad idea to stop every once and a while, to clear out some of the more dangerous soldiers before advancing on and attracting more soldiers to your position. After the last set of crates, you will see some submarines, signifying that the stage is almost over.
In order to escape the Harbor and advance to the next stage, you will have to get past the enemy's security guard and their forces of attack German Shepherds. They will attack you in waves from both the left and the right. They start on the left with lighter dogs which will leap for your throat. You can safely attack these while remaining standing. Then they will appear on your right with darker dogs which attack your legs. These must be attacked while crouching down on the floor. The attack waves will alternate with the time between them diminishing until you have completed three full rounds of each.
 NES differences
On this stage, you can obtain unique special weapons from the supply runners such as the invincibility star, which is only provided by the very first supply runner, and the pistol. Grabbing the star will allow you to proceed through nearly half of the stage without fear of getting killed. You can get a pistol from the last supply runner before the crates, which is on the bottom level in the American version, and the middle level in the Japanese version. The pistol allows you to fire bullets for the duration of the special back ground music. There are no parachute soldier in this version, but there are a lot more combat specialists. Be very careful jumping or falling off crates to the ground below, as there are typically land mines beneath. When fighting the dogs at the end of the stage, you must always lay on the ground, and they will never jump for your throat. You will have to fight six dogs from the right, six from the left, six from the right, six from the left, and finally six dogs which alternate left, right, left, right, left, and right.