Given that this episode was originally set to be a pilot for a Gary Seven show, and that it features odd cinematography (shooting around the fact that Kirk and our heroes rarely occupy the same space together), not to mention weird ideas that never get mentioned again (like time travel to the past as a thing that Starfleet ships just DO as a regular basis), should we regard this episode as a part of Star Trek canon?
A couple other problems I noticed are:
1. Gary Seven, presumably a human, is immune to Spock's nerve pinch. Why is never explained.
2. At the end, Kirk says that he's sure that Seven and Roberta Lincoln will have "many interesting adventures together", a nod to the show that never came to be.
Is this episode too full of in-jokes and nods for its own good? Is it too "meta"? Sometimes I think so.