Another Dimension is the name given to the interdimensional space or tunnel between Halcandra and Planet Popstar in the Kirby series. It serves as the final level of Kirby's Return to Dream Land and is where Magolor is defeated. It is also the home of the Doomers, Sphere Doomers, the Grand Doomer and the Greater Doomer. It is generally accessed via blue star shaped dimensional rift.
Another Dimension also serves as the main setting of the Heroes in Another Dimension mode from Kirby Star Allies, where Kirby and his Dream Friend must fight against parallel manifestations of characters from Kirby's dimension to save Hyness from the darkness of the Jamba Heart.
Kirby's Return to Dreamland
Throughout the game, various dimensional rifts will open, which leads Kirby, Meta Knight, King Dedede and Bandana Waddle Dee to fight Sphere Doomers for the Energy Spheres they have stolen. It is later opened by Magolor using the Lor Starcutter's Halcandran technology in order to start off his scheme of universal conquest once he had stolen the Master Crown. Magolor is however defeated inside Another Dimension thanks to Landia's help and the Master Crown is destroyed. Without the Master Crown to create a stable passage between Halcandra and Pop Star, the whole dimension collapse as the four heros returns to Pop Star.
Kirby: Triple Deluxe
Kirby: Planet Robobot
It is implied that Susie was sent to Another Dimension as a result of one of Star Dream's experiment, which led her father to believe that she died and kickstarted the whole series of events that led to Kirby: Planet Robobot. It is also where Susie got the data on the Sphere Doomers that allowed the Holo Defense API to recreate them.
At the end of Meta Knightmare Returns, Star Dream summoned Galacta Knight from a portal similar to those that leads to Another Dimension. It is also possible to see the Lor Starcutter flying through what looks like Another Dimension when Galacta Knight tears the fabric of reality appart in one of his attacks.
Team Kirby Clash Deluxe
In Team Kirby Clash Deluxe, Greater Doomers emerges from a portal leading to Another Dimension just before his fight. Parallel Susie, which is a Mirror World version of Susie, also comes out of a similar portal and is taken back into one after her defeat, which is supposed to mirror what happened to her regular world counterpart.
Kirby Star Allies
Another Dimension is the main setting of the "Heroes in Another Dimension" mode where Kirby and his Dream Friends must travel across Another Dimension and gather the Friend Hearts that were scattered across it. After defeating the four parallel incarnations of some of Kirby's most well known foes, Kirby manage to gather the four Heart Spears that where also hidden in Another Dimension. The Star Allies then use these spears to break the Jamba Heart which formed around Hyness when he fell into Another Dimension and became corrupt. After defeating him and the three corrupted Jambastion Mages that came to his rescue, Kirby uses the power of the Friend Hearts to free their hearts from the darkness once and for all. Another Dimension is then restored to a more calmer state thanks to the mages' power.
Parallel Susie is the parallel version of Susie. Like Susie was, she appears to be trapped in alternate realities and dimensions. The main difference between the two is the lack of the Haltmann Works Company logo on Parallel Susie's mech suit which could imply that she is not affiliated with them. She also lacks her hair accesory which is said to be the most precious possession of the regular Susie.
Parallel Landia is the parallel version of Landia. Parallel Landia is however said to have succumbed to the power of his world version of the Master Crown and is controlled by it like Magolor was in Kirby's Return to Dream Land.
Parallel Dedede is the parallel version of King Dedede that was created from the Jamba Heart that came in contact with Dedede during the main storyline of Kirby Star Allies. Parallel Dedede is said to be a tyrant fueled by pure rage unlike the regular Dedede who is way more tame and merciful.
Parallel Meta Knight
Parallel Meta Knight is the parallel version of Meta Knight that was created in Another Dimension when Meta Knight was corrupted by one of the Jamba Heart. Parallel Meta Knight is said to be a twisted version of Meta Knight who follows his own deviant code of conduct based Meta Knight's usual chivalrous code.
Parallel Woods is the parallel version of Whispy Woods, unlike the regular Whispy Woods, Parallel Woods is said to be a rotten arbor imbued by the incredible dark powers coming from the influence of the Jamba Heart that corruppted Whispy during the main story of Kirby Star Allies.
Parallel Kracko is the parallel version of Kracko that was created when Kracko came in contact with a Jamba Heart during the main story of Kirby: Star Allies. In Another Dimension, Parallel Kracko seems to be a manifestation of negative energy fueled by the foes he has defeated in the past. Like every other Parallel versions, Parallel Kracko seems to be a dark exageration of its regular world counterpart, in his case, Parallel Kracko appears to be an exageration of Kracko's usual agressiveness toward those who trespass on his territory.