Since this is a Nolan film, the plot is dense. Pay close attention to the explanations of and the Tesseract in the final act. If you're watching with subtitles, ensure they are high-quality, as the technical dialogue is crucial for understanding the ending.
If you are watching with Vietsub for the first time, keep an eye out for these pivotal terms:
They first visit the planet of , near Gargantua. Due to time dilation (1 hour = 7 Earth years), they land on a water planet — only to realize Miller arrived minutes ago (years earlier in Earth time). A giant wave kills Doyle, and they escape, but 23 years have passed on Earth. Cooper sees video messages: his son grew up, married, had a child, and Murph (now an adult scientist played by Jessica Chastain) accuses Cooper of abandoning them.