The 2 things that really stood out to me were the fight music and Spocks emotional "leak." I really appreciated the look into the Vulcan way of life. If I recall, that was the first episode in which the Vulcan hand greeting makes its appearance. Leonard Nimoy tells a story about how he made it up on the spot but the actress playing T'Pau was unable to replicate it, so they had to hold her hand in that position below the camera and then she just brought it up into view of the shot when called upon.
"Stop it? I'm counting on it."
"But not because you threaten me. I'll pay you because... it's my pleasure."