Out of bounds
In the Pikmin games, it is possible to use exploits or glitches to go out of bounds. Having a leader or Pikmin outside of the normal area boundaries allows players to take shortcuts, reaching certain points before they're intended to, or to go to places they're never intended to reach.
Below is a list of places where it is possible to go out of bounds.
On the ramp in The Distant Spring near the UV Lamp, it is possible for Olimar to go out of bounds by getting pushed by a Spotty Bulbear. The player must awaken the Bulbear, go about halfway up the ramp, while the Bulbear goes to the side of it. The Bulbear will try to bite Olimar, and assuming that Olimar and the Bulbear are facing the same direction, Olimar should be pushed out of bounds. This glitch is usually used in speedruns, as a faster way to collect the Chronos Reactor.
One can do a similar feat in The Forest of Hope in Challenge Mode, by going to where the Shock Absorber is in story mode. There, the player can wake up the Bulbear, and have it shove Olimar down below the stage, where he will respawn out of bounds. This is done by going to the wall, lying down and having the Bulbear lunge. Sometimes, the Bulbear will push Olimar underground, to where he will respawn on a normally inaccessible ledge. From there, the player can walk all the way around the area, while removing Olimar’s collision detectors on some objects. Using this, one can also enter areas where they normally can't, until a gate has been destroyed. However, with no Pikmin in Olimar's party, he can become trapped behind these walls.
In The Distant Spring, in Challenge Mode, go to where the Chronos Reactor is in Story Mode. There will be a Yellow Wollywog next to the Pearly Clamclamp. Lure the Wollywog over to the hole in the east wall, where a second one can be found close by. If positioned correctly, both Wollywogs will try to jump on you. Lie down next to the wall, and if done correctly, Olimar will clip on top of the wall. Staying on the wall, have one Wollywog follow you over to the place where the Chronos Reactor is in Story Mode. Being careful not to fall off the wall, you can lure the Wollywog up on top of the wall with you. Lure it to the invisible wall where the Reactor lies. Lie down and have the Wollywog jump on you, and if done correctly, Olimar will be pushed past the wall, with no way to get back in bounds. He will start walking automatically into the abyss, with no way to change his direction. The Distant Spring will fade into the background as Olimar soon passes the skybox and is surrounded in nothingness.
Olimar can also be pushed by Bulbears through the tree stumps in The Distant Spring.
In Pikmin 2, there are several ways for one to go out of bounds. The effect of these exploits varies by location.
One method of getting out of bounds uses the boulder jump glitch. When a leader lies down, they make a small bounce. If they collide with an Armored Cannon Larva or Decorated Cannon Beetle rock, or a falling boulder, then they will bounce high in the air, and potentially land out of bounds.
Another method involves going near a sloped wall that one wants to go out of bounds on, and making the leader lie down. A Pikmin will automatically pick the leader up, and with some walls, and some Pikmin types, the Pikmin will carry him up the wall.
A leader can also clip into the ground using the seesaw glitch, and end up appearing out of bounds.
In garden-type sublevels of caves, a glitch can be used to get over the boundary wall.
In Pikmin 3, going out of bounds is often done by throwing a leader in a certain location, such as on top of a dirt mound, or by wedging on the side of certain edges, as in the Yellow Onion cave in Distant Tundra. Another way is to use a technique that makes use of wedging into a corner, getting a leader into the scenery, and whistling and dismissing. The final way is by the dodging, by using it to get from an elevated place to out of bounds. An example of this would be on the ice slide in Distant Tundra.
Being a 2D game, Hey! Pikmin has less opportunities for going out of bounds, but it can be done in some places.