What about that OS episode where Kirk drank from the fountain and was sped up to a superfast metabolism, and his phaser was (relatively) slow enough to walk out of the way from the beam at point blank range ...
They had some super-light technology for their weapons, that could only be heard it was so fast! Wow!
(In other words, more evidence of ST's lack of science credentials.)
It became very obvious to me how the writers were creating their scripts. Technology was added at particular points in the script as plot devices (we need comms blackout here, or no teleportation here).
That's why I classify it more as a romantic fantasy than a SF story.
Having said that, it really is a continuum, I think. I don't think there are hard and fast boundaries to compartmentalise the different genres.