This is the 10138th most frequent Japanese word.
重たい
Heavy.
Here, '重たい' conveys a sense of heaviness in the atmosphere, describing an oppressive or stifling mood.
空気が重たくて、部屋の中にいると息が詰まりそうだ。
The air feels heavy, and it is suffocating to stay in the room.
Here, '重たい' means physically heavy, describing the weight of the box.
この箱は重たいから、一人では運べません。
This box is heavy, so it cannot be carried alone.
In this sentence, '重たい' refers to a figuratively heavy or serious topic in the movie.