Jumba has recently created Experiment 626 (a.k.a. Stitch) and has high hopes for this one. Jumba sends 626 to go on a mission across the galaxy to collect DNA, replacing 621 in the mission as Jumba was disappointed by the earlier experiment's efforts. Throughout the game, 626 causes destruction in his quest to collect DNA, and comes across various enemies along the way including Captain Gantu, a rival evil scientist to Jumba called Dr. Albert Habbitrale, and an increasingly jealous 621, who goes out on his own to find DNA in order to mutate himself into a much stronger creature.

Despite this game's ambitions, it received a mixed reaction from critics, who had issues with the gameplay, camera, and graphics. The game would be retconned out of the Lilo & Stitch canon over the years, with Dr. Hämsterviel becoming the franchise's main villain over Habbitrale and Lilo & Stitch 2: Stitch Has a Glitch fully establishing what actually happened before the original film. 621 would never make another appearance in the franchise, although he would be named "Chopsuey" by the events of Leroy & Stitch.

Tropes relating to Disney's Stitch: Experiment 626 include:

• 100% Completion: The game is complete when all of the DNA and film reels are found.
• Aliens Speaking English: All of them, with the exception of 626. It is a Lilo & Stitch video game, after all.
• Bloodless Carnage: 626 destroys everything he touches, including United Galactic Federation soldiers, without drawing any blood.
• Bullet Time: 626 can slow down time to a crawl, even while jumping.
• Call-Forward: The game had some statues that resemble traditional Hawaiian tikis.
• Canon Discontinuity: The game was rendered non-canon three years after its release by the flashback scenes of Lilo & Stitch 2: Stitch Has a Glitch, which depicts Stitch's true origins.
• Canon Foreigner:
  • Experiment 621, who was only made for this game and has never appeared in any other work in the franchise.
  • Subverted for Dr. Habbitrale. Although it seemed like he was made for this game based on the silhouetted prisoner who looks like Dr. Hämsterviel in the prologue of the original film, a model sheet for the original film has revealed that he is that prisoner. Said model sheet even shows that he has the first name "Albert", which was not mentioned at all in the game.
• Checkpoint: There is a checkpoint system via stepping on a blue button.
• Combat Commentator: Jumba and 621 are both somehow aware at what 626 is doing during gameplay.
• Covers Always Lie: 626's container is never seen in the game.
• Darker and Edgier: Compared to the original film, it focuses directly on sci-fi combat.
• Doomed by Canon: Not that canon accepts this game anyway, but Habbitrale was thrown out the airlock. Model sheets for the first film confirms that he would be found and imprisoned by that film.
• Early-Installment Weirdness:
  • 626 is not only known as an experiment but also a mutant (not "mutant koala" or "mutant dog", just the lone descriptor "mutant").
  • The game introduces the 700 series (or "7-series" as it would be called now) of Jumba's experiments, inexplicably skipping over most of the 600 series (6-series). The franchise would later establish that Stitch was Jumba's last experiment before his arrest, and his only later experiments would be 627, 628, and Leroy.
• Evil Versus Evil: 626 and Jumba are unreformed villains here and they fight off against 621 and Dr. Habbitrale, who are also evil.
• Exposition Fairy: Jumba and 621.
• Expressive Health Bar: The health bar includes an icon of Stitch's head where his expression changes as he loses health, gradually looking more worried. When he dies the icon shows him knocked out.
• Final Boss: Captain Gantu.
• Foregone Conclusion: Jumba and 626 escape at the end of the game, and Gantu vows to capture them both. It's safe to say that he or his employers would succeed later on.
• Forced Tutorial: The first level.
• Freeze Ray: One of 626's guns is this.
• Gotta Catch Them All: 626 has to collect a certain amount of DNA in each level.
• Green-Eyed Monster: 621 hates that 626 is getting all the positive attention from Jumba, so he goes on his own collecting DNA in order to prove himself as the superior experiment.
• Hannibal Lecture: 621 gives one away before he mutates.
• Hero Antagonist: Gantu is the Big Bad of the game, but he's heroic while 626 and Jumba are not.
• Humongous Mecha: Dr. Habbitrale's "IROB", a giant robot fought as the first boss.
• I Am the Noun!: Gantu declares that he is the law.
• Invincibility Power-Up: 626 can find a lightning bolt that makes him both invincible and golden for a short period of time.
• Jungle Japes: Some levels take place on an unnamed jungle planet.
• Life Meter: 626 has this in conjunction with his mana meter.
• Loading Screen: In between levels, there are loading screens with frames based on the original film.
• Mad Scientist: Both Jumba and Dr. Habbitrale qualify, the former through the creation of his genetic experiments, while the latter mutates already-existing creatures.
• Mana Meter: 626 has this in conjunction with his health meter.
• Market-Based Title:
  • In Japan, the game is known as Lilo and Stitch: Stitch no Daibouken ("Lilo and Stitch: Stitch's Great Adventure"), even though Lilo does not appear in the game with the exception of the clips re-used.
  • In Korea, it's called Lilo & Stitch: Stitch 626, which not only has the same issue as the above Japanese title but also oddly makes Stitch's experiment number a surname of sorts.
• No Name Given: 621 is never given a proper name here but was later named "Chopsuey" by Leroy & Stitch.
• Not-So-Harmless Villain: Both Habbitrale and 621 qualify.
• One-Winged Angel: 621's mutated form, with huge bugged-out eyes, long limbs, and a much more menacing appearance.
• Palette-Swapped Alien Food: "Alien toes", which look like bright green, purple-spotted chicken drumsticks like the one seen in the movie.
• Pass Through the Rings: The jetpack levels all require the player to fly through rings. The in-game explanation is that they serve as the jetpack's fuel.
• Pre-Rendered Graphics: All the game's pre-rendered cutscenes use somewhat crude-looking CG animation.
• Power-Up Food: The aforementioned chicken drumstick-esque alien toes restore health.
• Recycled Soundtrack: The game uses a bit of Alan Silvestri's score from the film during the cutscenes.
• Scenery Porn: While the designs are rushed, they are filled with detail.
• Three-Act Structure: The game has three acts, each with a boss.
• Thrown Out the Airlock: Habbitrale's fate, while inside a hamster ball.
• Unlockable Content: Clips and promos for the original film can be unlocked by collecting film reels.
• Villain Protagonist: Since this takes place before the original film, 626 is this, as he is fighting off intergalactic law enforcement to collect DNA so he can help his creator make more illegal genetic experiments.
• We Will Meet Again: Gantu promised to catch 626 after their encounter.