The mismatched-buddy cop picture has literally and perhaps inevitably gone to the dogs, and the only notable thing about K-9 is that it managed to dig up the idiotic premise first.
Since the black-white pairing in 48HRS., there have been numerous cop film teamings. K-9 has all the trapping of its precedessors: a flimsy plot dealing with the cop (Belushi) trying to break a drug case, an unwanted partner (Jerry Lee, a gifted German shepherd) being foisted on him and a grudging respect that develops between the two during the course of a series of shootouts, brawls and sight gags.
There are a few amazing moments (the dog’s rescue of Belushi in a bar). In between lingers lots of standard action-pic fare, plenty of toothless jokes and some down-right mangy dialog.