I found the title of The Killings at Outpost Zeta thanks to a thread on this site. Now, I´m again looking for another movie that is almost at the same level as the other one. I´ll try to make a synopsis.
There are 5 or 6 characters trapped in a house. They don´t know how they got there, they don´t know how to leave the place. But they find some rooms to occupy and some games to play.
They are being observed by a trio of aliens whose silhouette looks similar to a human shape, but they are covered in crystal. So we can not see their eyes and facial features.
What the aliens are doing is testing human responses to different stimuli, even though sometimes the humans respond harshly and violently to each other and kill some of them by playing the tests games the aliens give them.
In the end, when it seems the aliens finish the tests and the experiment on the human race specimens, one man appears walking on a dirt road and enter a bar. There he asks for a drink and whistles a tune. A woman listens the tune and stops, wondering why the tune is so familiar. So she approaches to ask, "Hey, excuse me", "Yes?", the man says, "Can you tell me where did you hear that tune?" The man stops whistling and thinks over. He seems confused. "I really don´t know", he says. "It just came to may mind." And then the woman apologizes for the bother and continues her way.
It´s clear that the experiment memories were erased from their minds. But is also clear that nobody died in the experiment. The aliens were just manipulating their minds or could reset everything back to the beginning.
More or less what I remembered. I don´t trust my memories in the sequence because I might have not watched the movie form the very beginning. What I think is that the beginning is the end of the movie.
The idea of this experiment which seems unfair and careless, and then changes just to return all the humans to normal, except their erased memories, was an idea that stuck to me to these days, decades away that when I watched the movie.
So, I hope someone would help me again with this movie.