The tie-in video game for Star Wars: Episode III - Revenge of the Sith was shockingly dark, even featuring an alternate ending where players could defeat Obi-Wan Kenobi on Mustafar. Though it hasn't aged as well as some other classic Star Wars games, such as Jedi Academy, and was only met with mixed reviews when it released in 2005, it has a surprising amount of violence for a game based on a Star Wars film. This was of course part of the pre-Disney Star Wars era, where more violence was allowed, but some additional gameplay sections delve deeply into the fall of Anakin Skywalker and the subsequent rise of Darth Vader.
It helps that Revenge of the Sith is perhaps the darkest of all the Star Wars films. A New Hope has the genocidal destruction of an entire planet and the heavily implied torture of Princess Leia, but Revenge of the Sith shows Anakin's catastrophic descent into the Dark Side of the Force. The movie has the beheading of Count Dooku (who, relatedly, could feature in Star Wars Eclipse as Yoda's apprentice), Anakin Skywalker's slaughter of the Jedi Younglings, and Obi-Wan severing all of Anakin's remaining limbs in one fell swoop, after which Anakin is ignited by lava and torturously transformed into the mechanical Darth Vader. Palpatine rises to power, the Jedi are betrayed by their clone allies, and is certainly one of the most violent Star Wars movies released.
Perhaps due to graphical limitations, the Revenge of the Sith game does not include Count Dooku's head rolling across the floor of Grievous' flagship, but Anakin does still unceremoniously execute him with a lightsaber through the torso. The really dark parts of the game come after Anakin has fallen to the Dark Side and it even fills in some gaps in the Revenge of the Sith film. After the death of Mace Windu (which Anakin performs in the game instead of Palpatine), Anakin brings Clone Troopers to the Jedi Archives and murders Jocasta Nu, the Chief Librarian. What follows is Anakin wreaking havoc across the Jedi Temple, fighting waves of young Padawans and cutting down any other Jedi who stands in his way. Following Order 66, Obi-Wan's missions are equally violent, as he kills countless Clones while trying to escape Utapau.
Episode III Game's Alternate Ending Shows Anakin Killing Obi-Wan
The Revenge of the Sith video game truly takes a wicked turn when it comes to an alternate ending only available in the PlayStation 2 and Xbox versions. In the climax of the fight on Mustafar, Obi-Wan's high ground does not give him the upper hand. Anakin successfully leaps over his master, puts his lightsaber through Obi-Wan's torso, and kicks his lifeless corpse down the slope toward the lava. Returning to the landing pad, Anakin is met by a celebrating Darth Sidious, who offers the recently christened Lord Vader a red lightsaber. Anakin takes it with a flourish and uses it to strike down Sidious, claiming the galaxy and the imperial throne for himself.
Star Wars: The Force Unleashed would also employ an alternate ending (which was further explored in Dark Side-themed DLC), but Revenge of the Sith as a package could be darker. Rather than the well-known, exceptionally dour transformation into the galaxy's most notorious Sith Lord, whose power is shown in Darth Vader's Jedi: Fallen Order cameo, the Revenge of the Sith game depicts a disturbing look at Anakin's newfound power. The in-action dialogue at the Jedi Temple has Anakin shouting about the power of the Dark Side as he easily crushes Padawans. He mercilessly kills his masters both old and new in order to seize control of the galaxy. Star Wars: Episode III - Revenge of the Sith is certainly dark, but the video game and its alternate ending have an even darker sequence of events.