King Dedede plays with a modified hammer ability. Since he cannot use Copy Abilities, he has added attacks and slightly more power. For cutting ropes and hitting distanced enemies with an aimed attack, he must simply charge his hammer. When released, will send out a laser-like red arrow attack. This is assumed to be the same red effect as the shock wave attack, which is used when using the hammer on the ground at full health. For melting ice, the Hammer Flip is still intact from every other version of this power. He can also use the Hammer Twirl to melt ice. The Hammer Spin is also intact, and uses a wind effect to put out flame blocks. It is otherwise the same.
There are several added features to this mode. The first is the addition of a time attack, which counts up through the levels. All the levels in a single world (minus the Hypernova segments) are compiled together into one level. The time attack also adds shortcuts, which allow players to skip to later levels in the world, or a later segment if one is found in a longer stage. The Warp Holes from previous Kirby levels return for this, and can be found in some of the locations that originally contained Sun Stones. If they were not hidden in a separate room, and are in the direct path of the level, the Sun Stone is replaced by a 1UP, which is the most common. As a separate feature to the time attack, there is also a difficulty boost in the form of a lack of health items. There are very few, and there are only Maxim Tomatoes before bosses, and in some of the harder stages. As another part of the difficulty boost, every boss and mid-boss is in its DX form, and a few of the normal enemies have the ability to move quicker, hit harder, or just become larger. This adds more difficulty to each battle, whether by being faster, harder hitting, or having different attacks added on. These are the same ones Kirby will be fighting in The True Arena later on.
As mentioned above, the levels have been edited to remove things that Dedede cannot accomplish without the Hypernova ability.
Key Dees run faster than usual and have a different fur color.
Kirby's stars have been replaced by shiny, multicolored Dedede logos. Values have not changed. There also seem to be more of them, as they appear after end of stage mid-bosses, which there are also a few more of.
With the replaced Sun Stones, there are actually more 1UPs than healing items, which may remove a bit of difficulty.
Stages are compiled into one level, and the player receives a ranking and clear time at the end of each "level." There are also save points at the end of each level, with a few being scattered between stages.
After Queen Sectonia DX is defeated, the Dimension Mirror appears and releases Shadow Dedede. He is a more aggressive form of Masked Dedede. He attacks much more rapidly, and at half health, becomes a more aggressive Masked Dedede's Revenge. He shatters into glass shards at the end of the fight, and Dedede enters the Dimension Mirror.
Dark Meta Knight replaces Sectonia Phase 2 as the final boss of this mode. It is unknown why he targeted Dedede specifically, but it may have been that he was the closest to the mirror. When he is beaten, Dedede smashes the mirror, trapping him once again.
Similar to how Meta Knightmare Ultra took place after Milky Way Wishes, Dededetour most likely takes place after Story Mode, as the statues Dedede smashed were already destroyed. This means that Dedede went back up the Dreamstalk for some reason, though there is no in-game explanation. The pause menu, however, says "This land will not be ruled by Queen Sectonia! No! It will be ruled by the king!" This implies that Dedede may be trying to take over Floralia himself, or otherwise annex it as part of Dream Land. This also would mean that Sectonia would have been revived in some way after the main story.
Dededetour's name is a portmanteau of Dedede and detour, where detour refers to the fact that Dedede is going out of his way to complete the stages Kirby has already completed.
It's a royal time attack with fewer recovery items than the main story mode!”
Jump into Warp Holes for a shortcut to stages further ahead!”
— In-game tutorial • Kirby: Triple Deluxe
Battle deluxe bosses along the way, and face a final boss who wants revenge!”
— In-game tutorial • Kirby: Triple Deluxe
After certain amounts of stages in a level, there are save points. This usually happens at the halfway point and before the boss. The theme is a remix of "Crash! Gourmet Race!" in worlds 1-5. In world 6, it uses a remix of "Great King Dedede's Theme".
King Dedede treks through all the normal stages in Levels 1-5 before then going into the extra levels that were unlocked by collecting all the Sun Stones in the level. Afterwards, he proceeds to go to Royal Road.
In the ending of Dededetour, the Dreamstalk seems to have shrunken in size, and the islands seem to be floating, rather than connected to the Dreamstalk as seen in the original ending.