Survival mode: The game only gives you a certain amount of pikmin and you are in an underground dungeon. The game also sends waves of enemies which you must fend off within a small area. You get points for each kill and the games ends when you either complete all the waves, your captains dies, or all your pikmin dies.
There are different levels and each level has a different layout (like circular, square, platform in the middle, etc.). One level is also an "Endless Survival" level.