Gotenks is considered one of the most powerful individuals in the Dragon Ball history, and is the youngest of all fusions. His size however, is greatly made up for by his power. He is able to make powerful transformations such as Super Saiyan 3, enormously boosting his power level. On the contrary, he is still inferior to the fusions of Goku and Vegeta, because these two Saiyans are stronger than either Trunks or Goten, so their fusion (whether beingPotara or Fusion Dance) is superior; as seen in Dragon Ball Z: Shin Budokai where Super Gogeta defeatsJanemba just as easily as he does in the film while Super Saiyan 3 Gotenks admits he is not doing any damage to Janemba. At Super Saiyan 3, Gotenks is able to surpass Super Buu's strength, though the Majin's endurance prevents him from being beaten before Gotenks defuses.
Gotenks' childish personality causes him to create many attacks, some of which are nothing special, while some deal hefty damage. Most of his attacks are only used once. He tends to give very basic moves complicated names. His habit of giving names to all his attacks (and subsequently only using them once), could possibly come from Vegeta, who has a similar, yet much less ridiculous, habit (Vegeta's most-associated attacks, such as theGalick Gun, Final Flash, or the Big Bang Attack, are each only used once in the manga). This habit is less apparent in the anime, as Gotenks and Vegeta tend to use those attacks more than once.
Super Ghost Kamikaze Attack: Gotenks' signature move. Gotenks expels Kamikaze Ghosts from his mouth for an attack. These ghosts are touch sensitive and explode when they touch anything, including each other. Gotenks also uses a Super Ghost Balloon which broke down into 14 ghosts.
Continuous Die Die Missile (Rapid Missile Fire in English): Gotenks' version of Continuous Energy Bullets, it is rapid fire of compact ki blasts. Gotenks performs this attack by firing dozens of continuous ki blasts, but they are a lot more powerful than the normal ones.
Splitting Headache: an attack that cuts the opponent in half. Gotenks fires a beam over his head which turns into a blade that drops down on the opponent's head, slicing them down the middle, before firing the Finish Flash to destroy the two halves.
Finish Flash: A double energy wave used against Super Buu to finish the Splitting Headache technique.
Kamehameha: The Kamehameha is used by Gotenks in the Budokai series and Dragon Ball Heroes. It is hinted that he was about to use it in the anime/manga when he charged up a final attack to finish off Super Buu shortly before returning to his base state as a result of fighting for too long, exhausting his depleting energy supply. As he is a fusion of Goten and Trunks, Gotenks should know this technique, as they both have used the move, as shown in Bio-Broly (the 11th Dragon Ball Z movie). This was obviously not shown in the manga, but Trunks alludes to knowing the move when he corrects Goten's mispronounciation of the move as "Kamekameha."
Big Tree Cannon: Obtained from Trunks. Used in the Budokai Tenkaichi series. This attack is similar to Vegeta's Final Flash, though not as formidable for the user's power.
Galactic Donut: A powerful gripping technique Gotenks performed. Gotenks uses this controllable halo (much like a hollow destructo disk) to wrap around Super Buu, constricting him within the halo. Super Buu, however, escapes by overpowering the ring, leaving it to disperse into small balls.
Charging Ultra Buu Buu Volleyball: A situational attack used by Gotenks when he once succeeded in capturing Super Buu (who had shaped himself into a ball) in several Galactic Donuts. The attack consists of capturing a target in many Cosmic Halos, trapping them inside a sort of cocoon and use the ball like a volleyball. Gotenks forced Piccolo to play with the ball, and then Gotenks followed up with an attack he called Spiking Buu Ball Slam (which was essentially one final hit to the ball), before Super Buu broke out. This left a huge crater beneath Kami's Lookout (that Buu had destroyed), and it was made even more massive when Buu fired a large beam from its bottom and Gotenks retaliated with his Die Die Missile attack.
Revenge Cannon: an attack where Gotenks, in his Super Saiyan 3 form, lets out a massive energy blast from his mouth. It is named in Dragon Ball: Raging Blast, but is also known as "Victory Cannon" in the Dragon Ball Z: Budokaiseries. A version of the mouth blast as originally used by Super Buu in their confrontation, Gotenks yells, "Revenge!" when using the move right back at him in response. For this reason, Super Saiyan 3 Gotenks shouts, "Rightbackatcha" when using the move in Budokai 3.
Vice Shout: both Gotenks and Super Buu had the ability to scream so loudly it tore holes between dimensions. Gotenks was only capable of this impressive feat as a Super Saiyan 3.
Among the named but unseen techniques, there is the Burning Annindo, Dangerous Machinegun Punch, Dynamite Kick Boomerang, Hyper Plasma Shortcake (ハイパープラスマショートケーキ, Haipā Purasuma Shōtokēki), Magnum Sundae (マグナムサンデー, Magunamu Sandē), Spiral Shooting Sobat, Thousand armed Goddes of Mercy punch (Senju Kannon Punch), and the Ultra Missile Parfait (ウルトラミサイルパフェ, Urutora Misairu Pafe).