It is a long movie and like most sci-fi the plot gets too thin to be believable at times. However the movie holds together really well overall and the proof of this is not getting a sore bum after sitting watching for just under three hours.
A large part of creating the right illusion in a movie is due to the sound and the sound design of Interstellar is remarkable. Whereas most modern action movies have used lots of gratuitous sound effects, each sound in Interstellar is carefully considered to add to the movie's story. This includes a pipe organ being used predominantly for the music, and silence for the outside the spacecraft shots. Foley, atmosphere, SFX, music, and dialogue are all well done, but at times not what we have come to expect. For example the organ is quite loud at times, total silence is used, tiny Foley sounds are present, and some dialogue is blurred into the other sounds. The net effect of this way of doing the sound is that it makes the movie seem more real, so I say well done.