The Part About Brainwave That Bothers Jupiter's Legacy Fans
Over the course of "Jupiter's Legacy," a great many mysteries are put before us, and not all of them are put to rest. Easily one of the most powerful jolts viewers receive by the end of the first season is the revelation that Walter Sampson, aka Brainwave, is, in fact, the mastermind behind the villainous activities that transpire over the course of the first six episodes.
This is a powerful revelation but also one that's a bit difficult to justify within the universe, as it really should have come a lot sooner than it had. And the lack of a proper explanation as to why Brainwave behaves how he does within certain scenes in modern times leaves the viewer potentially frustrated with the final revelation, as Brainwave not only seems intent on fooling his teammates in the Union of Justice but also himself (and by extension us, the viewing audience) as well.
Brainwave's actions represent a tangled web
In a reddit post by user HarryDresden1984, a case is argued that "Jupiter's Legacy" is not playing fair with the audience. On at least two occasions, Brainwave is alone within his "mindspace", a psychic realm that is fully of his powers' creation. Yet he behaves as though he has to continue the lie that he's performing for his family and teammates in reality. He talks to the Blackstar clone as if he's unaware he's actually a duplicate of the original. He also stages the battle between himself and the mental projection of Skyfox long before any of his teammates are on hand to witness his deception.
So why engage in a performance when no one is there to witness it? (No one, save the audience, that is.) With no other context, viewers are left with the conclusion that Brainwave was acting the way he was for no logical reason, except that the creators of the series wanted to hold the revelation until the final moments where Walter is revealed as the true villain of the piece.
There may be a possible explanation for Brainwave's behavior
There could be a possible explanation for this behavior, however. While a powerful telepath, Walter can't monitor everyone all the time and gauge their suspicions of him, nor can he be certain he won't give himself away somehow. In a family of superbeings with more than just heightened physical strength and superhuman powers, there is also a complement of super-senses — such as his brother the Utopian's super-hearing — that could give him away. It's possible Brainwave engages in this elaborate self-deception so he himself can believe it wholeheartedly in a form of self-hypnosis, which would keep any potential signs (body language, irregularities in heartbeat, etc.) from exposing his lies to the Union.
While initially appearing to be a move without any sense, these exercises in telepathic theater may serve a purpose. Brainwave may be burying his traitorous thoughts beneath impressions and ideas that seem so real he can believe in their veracity even as he meticulously creates them as complex thought constructs. So what appears on first viewing to be a kind of continuity error could hint at Brainwave playing a deeper game. In any event, it's certainly fun for "Jupiter's Legacy" fans to speculate.