The gameplay mainly remains unchanged from it's predessesor and most Mario Kart games in general. The main goal in most modes is simply to get the best place in the race out of ten positions, all while utilizing items. Underwater, Gliding and Gravity sections also reapper and more focus is put on them as opposed to pass games. Specail items return and so does basic interactions with both passengers, the player in the front controls the kart while the other player can utilize items, two items can be held at a time and the item the driver has must be passed back to use, both players can swap positions at anytime. The coins system is also absent.
Special Items also make a special reappearance and may appear based on what character is in the back, each duo of corroponding characters share the same specail item but two different characters from diffrent respective pairs can be switched constantly to change which specail item can possibly appear. Also there are many different karts with diffrent weight categories, Small, Medium and Large and any character above one size cannot be a passenger on any of the sizes belkow, meaning small characters can ride all vehicles while large characters can only ride large karts.
Rhythm Sections are an all new addition to sections of the series which add a whole new way of accelerating the vehicle, when enterd the cource and atmosphere itself will becoem gold colorated and flashy. Now to accelerate the player must press the accelerate button in time to the rhythm, or they'll start to halt. The beat's notes scroll along the hud and by passing certain gates called Note Gates in these sections more notes are added to mess up the player but grants acsess to specail shortcuts as well.
The player also gets faster and faster as they keep the beat but more at risk of bumping into a wall or object messing up thier combo. By bumping into opponents they trade beats adding even more difficulty. If two players are present on a kart the other player must also play a seprate beat.
Item Fusion is a new feature that complements the game's returning double system. Now when both players have an item the player is offerd the choice to combine both items creating a new item based on qualites from both items. This expands the heavily emisised item system it's predessesor had, opening up new opputunities to expiriment and find which combonations a player likes best. Specail items of course cannot be combined as well as regular non combineable items that whouldn't fit into item combonation, such as Pirahna Plants, Boomerangs, Super Horns and Spiny Shells.
Based off of the system of the same name mainly appearing in spin off sports titles, chemistry gives the player another reason to carefully choose characters. Certain characters have a postive relationship and when paired they lent a stat boost, with the boost depending on the character; ex Mario granting more speed and Luigi more handling when paired up, some characters may have a split addition of addign two boosts but only with half the quality as a half a chemisty boost. There are also of course bad relationships that decrese stats instead of boosting them.
If there are two human players occupying a vehicle at anytime they can split the kart into two identical karts sans the back seat. This allows both players to drive around via split screen at the cost of decreased weight and the ability to only hold one item. At anytime they can reconnect but they must both be in a certain range. Both players can also see information like what place thier partner is in and what item they have, and as long as they don't have an item they can deliver thier item.
These modes typically involve racing and such.
A reoccurring mode in the series where either one or in this case due to the Double Dash feature two players can play. As expected the player can play one of eight different cups with each halve being new and retro (returning from previous installments) cups. The player only stars out with the first new and retro cup and must clear cups with a gold trophy to get the next cup in it's respective category. To win a gold trophy the player must get the most points of all opponents, and points are won between races, the amount ditirmined on how high the place the player ended in.
There are four difficulties being 50cc, 100cc, 150cc and 200cc as well as two odd difficulties: Mirror Mode (reverses the track making right turns left and vice versa) and the new Reverse Mode (reverses the player's essensial goal, makign it so they must go through the course backwards as opposed to forwards, sometiems adjustments are amde to some trakcs to make this possible. everything above 50cc must be unlocked by completing the next mode in line and Reverse and Mirror modes are unlocked together.
One player must accomplish a full course sans any opponents or items, with the exception of both players having two mushrooms (that can be fused to make triple mushrooms). This is mostly a race against oneself and some things can even be unlocked this way. The player can also race agaisnt a ghost of their best time in attempt to override it.
A returning single player mode with somewhat different gameplay. Players must complete different challenges on diffrent courses ranging to collecting coins, passing through hoops or diffrent missions altogether. The similarities end there as it has a Super Mario Galaxy style of gettign to missions, each course is akain to a galaxy and most require a certain amount of flags, given to a player after a mission. Each course has two missions, with the second set being unlocked after the completion of all missions.
A costomizable exhibition race, although nothign can be unlocked here the player can fully customize the rules, actions, mechanics, the ability to disclude Rhythm Sections and certain items.