Plot hole: As shown when Robin comes under the influence of Slade's mind control device, the hypnotized people retain their abilities and higher intelligence, just with a loyalty to Slade. That being said, when Slade hypnotizes all the DC heroes, Superman and The Flash are among them in the theater. Slade orders all the heroes to chase after and destroy the Teen Titans. The Titans take off on foot with the others running after them and are able to keep their distance in a big chase sequence. Superman and The Flash never use their super speed to over take the Titans, which would have been so very easy.
Plot hole: During the climax with Van Helsing and the Kraken the writers of the film seemed to have forgotten about the powers Dracula has always had. At no point does his super speed or indestructibility ever come into play, he could have easily climbed up to the DJ booth and dealt with Van Helsing in seconds instead of going through the silly DJ battle.
Suggested correction: The kraken was faster and stronger than Dracula, if you watched he kept trying to reach the DJ booth and fight but was stopped each time and nearly crushed. It was said that the kraken was extremely strong and the only thing that could subdue him was a more powerful song than the other.