This is the 2202nd most frequent Japanese word.
物足りない
"物足りない" means "unsatisfactory" or "missing something."
Here, '物足りない' expresses that the sweetness of the cake is insufficient to meet the speaker's expectations or desires.
このケーキは美味しいけれど、甘さが物足りない。
This cake is delicious, but the sweetness is lacking.
In this sentence, '物足りない' is used to describe the impression that the movie plots are insufficiently engaging or satisfying.
最近の映画は何だかストーリーが物足りない。
Recent movies somehow feel like their storylines are lacking.
Here, '物足りない' refers to the feeling that the atmosphere is missing some element to make it fulfilling or complete.