Even though Black Manta and Bizarro are at the government base stealing the liquid light, they simultaneously appear at the trial in the Hall of Doom.
During the trial scene, keep your eyes on Scarecrow and Toyman. They switch positions at the Legion of Doom table at least twice.
After the android Green Lantern is trapped in the green energy bubble, the real Lantern is able to reach through and take his ring back. Yet, the bubble was supposed to entrap the real one forever.
If Green Lantern is separated from his power ring, he should have reverted to his plain clothes appearance of Hal Jordan.