The Cinema Snob says
The Last House on the Left (1972) is Certified Fresh on the film review aggregator website Rotten Tomatoes. To be Certified Fresh, films need at least 40 Tomatometer reviews, including 5 from top critics, and have a score of at least 75%. (Unless the score drops below 60%, films remain Certified Fresh.) When this episode came out, this film only had 30 Tomatometer reviews, including 4 from top critics, and had a score of 63%.