Continuity mistake: When the Daleks capture the TARDIS in the chronon loop, the TARDIS is the right way up. But when it is being pulled towards the Crucible, it is upside down. (00:06:22)
Plot hole: Near the end of the episode, the part-human Doctor is said to have all of the memories of the original Doctor. If this is true, then the part-human Doctor should remember the time the original Doctor spent with Rose, so shouldn't commit genocide or need Rose to help him to not be a man of killing.
Plot hole: Davros said that the reality bomb would destroy all parallel universes. He fails in the Doctor's universe, but the Doctor said in an earlier episode that every decision creates a new parallel universe, like if Donna had walked out of the TARDIS with Jack, Rose, and the Doctor. She wouldn't have imbued herself with Time Lordness, so Davros would have succeeded. This means that all the universes, including the Doctor's one, should have been destroyed, because if the Reality bomb only succeeds in one universe, it would destroy all the others as well.
Continuity mistake: When Martha arrives at Osterhagen Station 1, she unbuckles the belt of her teleport backpack, but in the wide shot immediately afterwards the belt is still buckled. In the next shot, it's back to being undone as she takes it off. (00:18:47)
Continuity mistake: When the Doctor, Rose and Jack get out of the TARDIS onboard the crucible, the console room is lit in very blue light. But in the shots of the console room before and after, it's lit completely differently. (00:09:15)
Continuity mistake: When Davros activates a screen in the Vault to show the Doctor and Rose the Reality Bomb test, the screen shows the prisoners being herded into the testing area, something that already happened shortly before. (00:23:14)
Chosen answer: No, no information is avalible for the identity of the entity.
Repo_Man