I watched Mulan on the airplane from Heathrow to Houston yesterday and paid rather close attention to ideas of transmediation, which is to say, how it moved from the film to the game. The Land of Dragons as Mulan's world is called in the game, is actually a rather easy transmediation/adaptation as there are only two real sources, the film and the game. There is, of course, the rough source from which Disney took the film, the Hua Mulan legend, but as the film was actually a combination of the legend and a short film called China Doll about a girl being whisked away from oppression by a British prince charming (according to Wikipedia). Sidestepping the film's issues of combining a Chinese legend about a tomboy and the Orientalist West to the rescue, the game takes the film at face value.
The game begins with a scene of Mushu prepping Mulan to join the army, and reveals that she is a woman pretending to be a man. This scene has similarities to when Mushu reveals himself to Mulan in the movie: both use the dragon shadow to make it appear larger and more frightening. Similarly, there is a fight when Mulan enters the camp between herself and three minor characters. This is repeated in the game, but Sora, Donald and Goofy have a larger role in both starting and continuing the fight. Both of these scenes involve adapting the film script and visual tropes into the game's cutscenes, but also adding the game protagonists.
The movie has a subplot of Shang being promoted to Captain and trainer of the new recruits by his father who goes off to fight Shan Yu. Mushu fakes a letter by the father in order to get Mulan into a battle (and thereby gain fame). This moves the troops to the second camp. In contrast, the game simply has a move to the second camp/town and removes both the father and backstory of Shang. Unlike the segmented adaptations that take scenes, some larger aspects of the film (that are nonetheless minor plot points) are removed and the game progression must be altered to make it fit. In this case, a secondary reason is provided to move to a similar setting (burned camp and large field by a mountain). In order to cover for this alteration (and burn the second camp) the game adds a cave into which Sora goes, skirking his duty, which results in Shan Yu burning the camp (not a town, like in the film). This adds action into the game and results in a switch from Shang's father as focal point to Sora, the player character, as focal point.
One visual element that is taken almost verbatim is the Emperor's throne room. Within the movie it is seen from a vertical angle. Within the game it is an explorable room that almost exactly reproduces the film version, but in three dimensions. However, I do not know whether the game programers had access to sketches of the Disney animators or if they rendered the world from stills of the film. The courtyard and inner castle hallways are similarly rendered between the film and game. However, other spaces, such as the cave in which Sora is trapped by Shan Yu, are unique to the game and it is unknown from where they get the visuals.
Action adaptation is limited within Kingdom Hearts as the game itself has its own activities: you fight, you use magic, you seal world, and the aspects of the worlds/films/stories that reside within the game are (primarily) the narratives and visuals. One world where this is decisively not the case is 100 Acre Woods where Sora actually does certain things that happen within the books. The reasons this sort of adaptation is possible is twofold: one is that Sora simply replaces Christopher Robin. Sora can thus follow the same actions that Christopher Robin follows within the books. However, what holds up this element is that the 100 Acre Woods world is devoid of both Heartless and fighting. It is (in all of the games) a world of mini-games that avoid the action requirement. Rescuing Piglet in the air, throwing Pooh to get the pot off of his head, et cetera, are all adaptations of actions within the books.
Kingdom Hearts has very few action adaptations. They exist within 100 Acre Woods and minorly in some other worlds (you must have Alladin in your party to use Abu to activate certain idols in the Cave of Wonders, etc), but such adaptation is limited. It is almost completely removed in Chain of Memories as the only place where the worlds/original stories have any bearing is in the three rooms per floor that involve boss battles or cutscenes (the action in action rooms is completely standardized other than visual representation). However, Kingdom Hearts II adds a larger number of mini-games and mechanical adaptations into both boss battles and worlds that much better utilize this form of transmediation.
The Mulan world of Kingdom Hearts II's has one major instance of action adaptation: the battle with Shan Yu where you must protect the door to the castle (and thereby the emperor). The game actually takes out all of Shan Yu's henchmen (it turns them all into Heartless who simply swarm the door), which means the cinematic adaptation level has changed. Instead of fighting in front of, within and on top of the castle as Mulan, Shang and friends do in the film, Sora's (and Mulan if the player has decided to have her in the party) battle with Shan Yu takes place entirely outside of the door to the palace.
In the film it is Mulan and company who are bared from entering the castle by Shan Yu and his group who have kidnapped the emperor and taken him inside (they climb up the giant columns to get inside). Then, within the castle Shan Yu breaks down a door in order to follow Mulan. The game takes the two mechanics of breakable door and barring somebody inside the large palace doors and flips it around to fit the game. Shang takes the emperor inside for safety, Shan Yu tries to break the door down and Sora and company prevent Shan Yu from breaking the door. If he (and the Heartless) breaks down the door (or if you die) you lose the fight, if you prevent the breaking of the door and beat him you win. The game adapts a active element of the film into a battle element of the game (Pirates of the Caribbean has a similar adaptation with the 802 coins and immortality as I wrote of previously).
There is a second type of action adaptation within World of Dragons, but it is only somewhat related to the film. After Mulan joins the army there is a song that follows through their pathetic beginnings and ends with them being fully trained. Essentially, it's a hollywood montage that quickens time and shows the troops (and Mulan) learning to fight. The game does not have such a scene and instead features three 'training' missions. The oddity is that at the beginning Sora can fight (both as this is not the first world visited in the game - he goes to Hollow Bastion first and either Land of Dragons or Beast's Castle second, but the real training level is actually Roxas in Twilight Town, so the player has experience, and as Sora as a character has already been in to previous games and is fully experienced fighter in the game world), but Mulan cannot. The training missions thus provide the training of the film, to get her up to snuff, but prove to be an odd aside for Sora and the player as they have no bearing on his quest. However, during this section there is an added 'tension' gauge (also called 士気, which translates to 'morale'). This meter must be kept up by collecting items that enemies drop when defeated and empties with time spent and when hit by enemies. If it ever empties completely the game is over. This gauge only occurs until Sora exclaims that Mulan is a good fighter, and therefore exists as a adaptation of learning, or education for the war situation.
It is also notable that one of the next fights after the tension bar disappears is when the previously mentioned 'door' mechanic is used. On one level such mechanical additions are 'adaptations' (they fit the source/target situations), but on another they are simply a gamewide means of expanding/complicating the fighting engine from its simplicity in the first game.
Another element that might be adaptable, or perhaps translatable might be a better word, especially in this situation, is choice. Within movies a character might choose something and thereby exhibit agency. Games attempt to reproduce this in morality options. This is seen in good versus evil morality mechanics of games like Fallout, Fable and KOTOR. In the case of KOTOR it is actually adapting a mechanic from the movie of how to work the light and dark sides of the force (it is doing this rather poorly according to many voices, but that it is attempting to do so is good enough for me here). This is an alternate form of adaptation, but it is one that the Kingdom Hearts game, because of its linearity, does not do.
Finally, I will try to explain the use of the term translation instead of adaptation. In common thought adaptation is a subjective reproduction, but also change of some original element. In contrast, translation is a one to one equivalence of one text to another. This is a very base understanding of both words in that translation cannot ever be a one to one equivalence between source and target text and it always involves subjectivity and politics. Adaptation, then, is a type of willful acknowledgment of the limitations of translation at the same time that it sets itself up as a changed (in some way) text. While the word adaptation might seem closer to the core of the matter in some circles, I would say that all of my above examples are actually types of translation.
Square is to rectangle as adaptation is to translation.