A gigantic bug is chasing grunts and snipers down a hallway, and manages to catch up to a few of them. The remaining soldiers run through a doorway and the bug follows. After an explosion a bunch of bug guts spill into the hallway, and then your character enters the base.
This level can get rather difficult, especially if its your first time through. Immediately up ahead are four pods and three large spiders (7%). Heavy weapons are better, however there are so many small spiders that you'll be better off with your rapid fire weapon. Two more large spiders are sitting around past the pods (9%). Five stems (14%) will pop up as soon as you get near them. You'll have to use your lock on weapons, and try to kill them quickly before the small spiders start to arrive. Three more large spiders and four pods (21%) are right past the stems, but if you approach slowly you won't have to fight everything at once. Past the bridge are three more pods and another large spider (25%). Kill everything and take the elevator down.
Two more stems and the only other walking labia in the game greet you (29%). Try to kill the stems before the labia appears and then move on. At the spilt in the path kill the two floating bugs (31%) and then go southwest to fight four more floating bugs (35%) and a group of black spiders. Kill the black spiders as fast as you can and while they're still bunched together. Once the move apart they are hard to hit. This is a dead end, so head back and southeast. Kill the black spiders before the large spider and floating bug (37%).
In the next area you have four stems, seven pods, and another large spider (49%). Kill everything and take the elevator down a floor. Destroy the group of four stems (53%) and then the next group of two stems (55%) and black spiders. At this point another one of the giant bugs seen in the intro will start to chase you. Don't bother fighting it or waste too much time with the spiders, just get to the elevator before it catches up to you.
- The elevator will start to descend, but the bug will jump down on to it.
Hit the Alien Bug as hard as you can with heavy weapons. Once it starts to use it's eye lasers you're going to need to use your spin move to avoid being killed since you can't out run it. After you kill it (58%), it will turn into the Alien Moth, which isn't too much harder (61%).
Once you get off the elevator you will be in a room filled with small spiders and alien heads the burrow underground. As you approach them they will pop out, at which point you should use your heavy weapons. Make sure you kill all ten of them (71%) before moving on. In the next room are two more alien heads (73%) and seven alien spawners (80%). At the end of the hallway is an Alien Door that blocks your way. First the lower segment (81%) must be destroyed, and then the eye (82%) before the way will be cleared.
Boss: Red Falcon
- When you enter the lab the floor opens up and Red Falcon's head appears.
- Once Red Falcon is flushed from the lab Master Contra appear, and it turns out that he is ... Bill Rizer. He claims that the other Bill is just a clone and he's been letting you fight in order to prevent the Assembly from finding out his real plans. After a few more words are exchanged he immobilizes Bill and Jaguar an prepares to leave.
One of two things will happen, depending on your ranking:
- If your average ranking is a C or D: While Bill & Jaguar are immobilized Master Contra transports to another base. He then raises the base into the Earth's atmosphere, powers up a laser weapon and destroys the planet. Game over, get higher rankings.
- If your average ranking is a B or higher: The two are immobilized by the field, but Mystery G reappears and stops Master Contra. He is fatally wounded and Master Contra leaves, but Bill and Jaguar can move again. Before he dies Mystery G tells Bill that it doesn't matter if he is a clone or not, he still lives by the original Bill's ideals so he is the real Bill Rizer. Bill asks him who he is and he replies that like Bill, he was once called "Contra".