From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Blast 2 moves are signature attacks for each character in the Budokai Tenkaichi video game series. Each character has two Blast 2 attacks. There are two variations of Blast 2's: beam attacks and rush attacks. Beam attacks are moves like the Kamehameha and the Galick Gun. They can be dodged pretty easily by a good opponent.
Rush attacks are short cutscenes of your character performing a barrage of hits to your opponents. However, it can be blocked if your opponents guard it, and so he can do a counter attack. The damage dealt by a Blast 2 technique varies with each fighter.
Along with cinematic rushes their are a few cinematic energy attacks (like the Spirit Bomb, Super Spirit Bomb, Father-Son Kamehameha, and Bros. Kamehameha) which produce a cutscene when they successfully hit the opponent. They also can clash (Energy Struggle) with other clashable Blast 2 techniques (for example the Father-Son Kamehameha can clash with Super Perfect Cell's Solar Kamehameha, allowing the player to recreate the climatic Energy Struggle that ended the Cell Games).