I always loved this one, even though it is pretty far away from what they were going for with the series. Kirk feels more like Christopher Pike, Spock repeatedly double-fisting Nancy in the face is hysterical, and nobody thinks to actually reason with this obviously intelligent creature.
As for it being a “typical monster episode,” I completely disagree. There’s a lot more going on to make the alien sympathetic. It’s a pitiable creature, not a monster and only the reveal at the end makes it one. You want to see “typical monster episodes,” pop on an average Voyage to the Bottom of the Sea
from the same year. Monster comes aboard, roars, kills the same stuntmen-characters over and over and is finally destroyed at the end. That’s it. The Man Trap did much more with its “monster” than most other shows of the day. The creature design is great and very sad while still being very creepy.
The rush to get this episode on the air probably accounts for the inconsistent sound effects (Communicators beep, don’t beep, chirp, don’t chirp, etc.) and use of stock footage from other episodes (common to the early episodes – not counting the ship shots) is peppered throughout. The music is barren and lonely, much like the creature itself. I also loved the electric violin employed liberally throughout the score. The opening theme was recorded at the same sessions and not used in the Blu-Ray release, where they plug in the cello theme recorded by Fred Steiner a little later on. The DVDs are still the only place to see the accurate opening title music and credits. God, I'd love for CBS/Paramount to release the series correctly. Just fricking once. But I digress...
This may not have been the ideal episode to kick off the series, but it is none the less an under appreciated story. The creature at the end is what seems to throw it off, but until those few moments of screen time, it’s a tense, somber and dark early take on the Star Trek universe.
It gets an 8 from me.