Throughout the multimedia DC Omniverse, time travel and manipulating the past seems to be a huge stumbling block. Certainly, no version of the Flash/Barry Allen since FLASHPOINT (comics, TV, animation, and probably film) has been able to pull it off without causing a cascading series of problems.
The Christopher Reeve Superman, however, seems to be the exception. In his 1978 movie (and the Donner Cut of SUPERMAN II), the Reeve Superman was able to time travel and manipulate the past with impunity. I wonder why it worked for him when it never worked for anyone else.
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