In Spain we don't usually say it this way. We just say "estar bien", but we don't use "estar buena". That expression is used when a boy says that a girl is very pretty and it vulgary means "she's hot", or something like that.
I think that the expresion "está buena", reffering to a film, is used by the spanish speakers in America.
In Spain, if you say that la película estuvo buena we understand that you ate the tape and it was tasty. But in other places (sp. South America) this is the usual expression.
Totalmente de acuerdo. Lo correcto en España es decir "las peliculas fueron buenas" o como tú tb dices "las peliculas estuvieron bien",, yo me quedaría con la primera opción, aunque la elección definitiva dependerá del contexto.. Lo que seguro NO se dice es "estar buena" en esta frase
No. Película is a synonym of film (both movie and tape and also thin layer that protects something). Going to the movies is ir al cine. If you want to use película you have to say voy a ver una película (al cine/en la televisión).
Indefinido means that there is no focus on when the action happened. It just means "this happened". On the other hand, imperfecto implies a focus on the development of the action in the past: "this was happening". The problem is that you translate both fueron and estaban as were in English and this difference that Spanish clearly marks with a morphem dissappears in English (and don't worry about this because many of the Spanish speakers who learn English have this very same problem when translating these tenses into English). I hope that the typical example we see when we learn the English tenses help you to clarify when to use one or another: El teléfono sonó cuando estaba viendo la televisión = The telephone rang when I was watching TV At one point in the past, the telephone started to ring. I was doing something (that I could kept doing or not)
Another example: El teléfono sonaba cuando yo estaba viendo la televisión = the telephone was ringing when (or while) I was watching TV. Both actions are simultaneous in the past. Someone was calling but I didn't care about the phone.
A third one: El teléfono estaba sonando cuando llegué a casa = The phone was ringing when I got home. The phone had started to ring, and so it kept, because there was nobody at home to answer. At one indeterminated point, I arrived home (and heard the phone ringing)
So, in this particular case, you are refering to something that happened in the past, without focussing on when or how long. It is just a statement: this happened. Of course, las películas eran buenas (which would be in English the films were good too) is correctly, but there is an implicit idea of "back in time..." (films were good). Sorry for the long post. I hope it helps (and sorry for my mistakes ;))