The game follows the movie storyline very closely, incorporating footage from the movie into the game and blending it well with the game portion itself. It involves playing through the events as either Anakin Skywalker and Obi-Wan Kenobi, with radically different events taking place in either. As Obi-Wan, much of the game is centered around destroying GeneralGrievous, while the Anakin levels chronicle his fall to the dark side of the Force and extermination of the Jedi Order. This includes Anakin's attack on the Jedi Temple, which culminates in a duel with Serra Keto, who happens to be the best student of Cin Drallig, who Darth Vader later fights and kills along with Keto. The game ends with the duel on Mustafar between Darth Vader and Obi-Wan. There are two different endings to the final battle, the first being that Obi-Wan defeats Anakin like in the film, the second being that Anakin kills Obi-Wan then meets the Emperor who gives him a new red lightsaber, Anakin in turn kills the Emperor and claims the new Empire for his own. The Game Boy Advance and Nintendo DS versions of Episode III are much the same to the console versions, except as a side-scrolling action game. The DS version also features uses for its touch-screen capability. The game was also released on the mobile phone and followed the storyline of all other versions.
Each battle can be won with either the best of one, three or five rounds, depending on the options chosen. In addition, all characters have equal health and energy, with all status upgrades acquired by Anakin and Obi-Wan eliminated to balance the fight against the other opponents. However, all of the upgraded techniques and Force Powers are available and each of the other characters has special abilities and maneuvers.
In addition to the original costumes found throughout the Single Player campaign, each character has a different costume that is used when each player chooses the same character, so that players can tell their characters apart. Some of these costumes depict Sith versions of certain Jedi characters and vice-versa.
In the DS version, there are 3D starfighter battles incorporating the touch screen to manage your shields and view Radar and scores. There are three missions for each Anakin and Obi-Wan in single player, and a multiplayer providing 8 maps and 17 ships:
In addition to the main story levels, there are bonus levels and characters the player can unlock and play as, such as Yoda, GeneralGrievous, an IG-100 MagnaGuard and Darth Vader. Most of these levels consist of the player mainly fighting wave after wave of enemies. An added bonus level is the player taking on the role as Darth Vader during his final encounter with Obi-Wan/Ben Kenobi in the original Star Wars Episode IV: A New Hope.
Most differences are about character deaths. Due to the fact that the game was released prior to the movie, many of the most important character deaths were changed so as to not spoil the movie. For example:
Obi-Wan and Grievous ended up in a room overlooking the sinkhole after fighting in a cave; concluding the chase with the General on his wheelbike, being pursued by the Jedi Master on Boga. This was instead of the chase concluding on Grievous's landing dock with his starfighter as in the movie.
Grievous doesn't cough during gameplay or 3D cutscenes, and he is killed when Obi-Wan stabbed him in the chest, and Grievous's armor short-circuited. In the movie, Obi-Wan used the cyborg general's own blaster to incinerate him with his gut sac exposed after Obi-Wan lost his lightsaber.
Mace Windu, instead of getting his hand cut off by Anakin Skywalker and having Palpatine throw him into the depths of Coruscant with Force Lightning, dueled Anakin and lost, being stabbed through the chest and kicked out of the window.
After turning to the dark side, Anakin often laughs evilly. In the film, he is quieter and prone to outbursts of anger instead of hubris.
Cin Drallig was killed with a saber impale variation performed by Darth Vader. In the movie, he was killed when Vader cut his chest.
On his mission, Vader kills Poggle the Lesser by using a piece of the door and a Force push to crush him. In the movie, Poggle is cut to pieces.
Nute Gunray escaped Darth Vader's slaughter. He tried to escape in his ship, and then to kill Vader, but Darth Vader destroyed the ship, sending it plummeting into the lava, and then exploding, killing Gunray.
When Darth Vader was defeated on Mustafar, Obi-Wan picked up his lightsaber and left without saying anything.
In the bonus level when Vader confronts Obi-Wan on the Death Star, Vader is able to cast Force lightning. That was not possible because of Vader's mechanical arms. Anakin, in the game, can also use Force lightning as soon as he turned to the Dark side, but in the film, he didn't learn that power at all, though it could have been possible. There are also TIE Interceptors in the background. However, that variant of TIE Fighter did not yet exist.
Palpatine's robe turns from red to black to red again during the fight with Mace Windu. This is because in the movie clips, it is red, but in the game parts, it is black - the same one he wore while captured by Grievous.
Mace Windu and Anakin both wear Jedi robes at the start of their fight, then they lose them, and at the end Anakin has his back on.
Padmé Amidala is never seen other than a brief appearance of her head, which is part of a clip from the movie, in the last two levels of the game and is otherwise only mentioned in the PS2 and Xbox versions of the game during the fight on Mustafar. She appears fully in the GBA and DS versions.
Nute Gunray and the others don't know they are being betrayed until Darth Vader arrives in the room, but in the game they realize Sidious' betrayal as soon as Vader lands, when he kills Neimoidian Guards and fights his way through the whole base to get to the council room.
Since Grievous got stabbed by Obi-Wan in the game he, of course, did not drop his lightsaber like in the movie. Also, in the movie Commander Cody handed Obi-Wan's lightsaber back to Kenobi seconds before Cody received Order 66 and tells troopers in turrets to fire at Obi-Wan. Instead, Obi-Wan Kenobi tells the clones to continue to higher levels. The clones reply by saying they no longer serve him and start firing at the Jedi Master.
Anakin joins the dark side because he sees Mace attempt to strike down Palpatine, thinking the Jedi are corrupt. In the movie, he joins the Dark side because Palpatine says he can help Anakin keep Padmé alive, knowing of the nightmares that Anakin is having.
In the GBA and DS versions there are missions involving Anakin fighting battle droids and an AAT on Coruscant right after he was appointed to the Jedi Council and once again after he decided to rescue Palpatine. Another mission involves Obi-Wan escaping from the clone troopers through the caves on Utapau and fighting several IG-Magnaguards on the way. There are also some minor differences like the fight with a Vulture droid aboard the Invisible Hand and an escape from the Hailfire-droid on Mustafar.
In addition to the above mentioned differences between the movie and the games, there also differences between various versions of the games as well:
The DS version of Revenge of the Sith, which is largely based on the GBA version, includes three space missions where Anakin or Obi-Wan (depending on who the player plays as) has to destroy some enemies and meet the objectives before moving on to the next mission.
The events of the duel between Anakin and Windu are played similarly to the movie with the GBA and DS versions in comparison to the PS2 and XBOX versions, barring that Anakin strikes Windu before they duel and that Windu is blasted with Force Lightning without being shown hurled out of a window.
As noted below, the "Ultimate Revenge Of The Sith" ending is omitted from the DS and GBA versions.
The mission "Revenge of the Sith" gives the player the opportunity to play as Anakin Skywalker/Darth Vader during the duel on Mustafar, with the objective of defeating Obi-Wan Kenobi. The duel plays out the same until the very end, where Vader avoids Obi-Wan's blade in his leap behind Obi-Wan to the lava river bank and stabs Obi-Wan with his lightsaber, killing him. He then kicks Obi-Wan's body near the lava. Vader then greets Palpatine as he steps out from his shuttle.
After being presented with a brand new Sith lightsaber and hearing Sidious say that he has "brought peace to our galaxy," Vader activates his lightsaber and stabs Palpatine. The clone troopers aim at Vader for killing Lord Sidious, then lower their weapons as Lord Vader says, "No...the galaxy belongs to me...!"
It is unknown if Sidious killed Yoda in this non-canonical ending, or if Yoda survived the duel. There is also no mention whatsoever in the game of the confrontation between Yoda and Sidious. However, it is possible Yoda was killed by Palpatine as he declares that "There are none left to oppose us." This alternate ending is named in the game as "Ultimate Revenge Of The Sith" as the Sith finally won against the Jedi.
Also, without Obi-Wan, Padmé would not be taken to Polis Massa and not be able to give birth to Luke Skywalker or Leia Organa.
The "Ultimate Revenge Of The Sith" is omitted from the DS and GBA versions of Revenge of the Sith, in which, regardless of whether the player is playing as Anakin or Obi-Wan, the ultimate outcome of the battle is that Anakin is cut down by Obi-Wan.
No original music from the film is used, since recording of the soundtrack had not been completed when the game's production ended. This is also the case in LEGO Star Wars: The Video Game. As a result, music from all of the other five movies is used. The cutscenes also use music from the other media. In the levels "The Final Lesson" and "Assassination on Mustafar," music from Star Wars: Knights of the Old Republic II: The Sith Lords is also used. This music can also be found in some multiplayer duel levels. Music from Episode III was not added in the 2006 "Greatest Hits"/"Platinum Hits" release of the game on PS2 and Xbox.
The Video game adaption of Revenge of the Sith used all of the original cast from the 2003 tv series: Star Wars: Clone Wars. However, Stock footage of the actors from the films for the films cinematic scenes. Alethea McGrath reprised her role as Jocasta Nu while Matthew Wood reprises his role of GeneralGrievous. Additionally, Christopher Lee recorded one extra line for Count Dooku: "Just because there are two of you, do not assume you have the advantage". This makes Christopher Lee, Alethea McGrath, and Matthew Wood the only actors from the movies to appear in the video game adaption.