Very fun episode, a classic meta-Trek that represents all that is good and bad in the series. Love it. I also have a real soft spot for fight scenes where Shatner does all his own stunts. His fighting is fantastic in this, especially the brawl in the teaser. The way he dodges Lars' knife and then lands a few solid punches is great. It's sad Koenig and Nichols look like schmucks in their fights, getting caught within seconds and chekov with his ridiculous jabs in Kloog's gut.
Kirk belting Shahna in the face is classic.
Stuff to look for: Shatner wearing his flats. Easier for fight moves. Kirk crushes his communicator when he rolls on the ground in the beginning. The grille is all bent. Kirk always touching the opposite color in the final fight with no penalties exacted.
I can't hate this episode. I just can't. An 8.