Knowing it was a risky show, the network shot two different finales: one with a cliffhanger in case they signed a second season and another one that ended the series. Because of the ratings weren't high, the series finished.
The original Life on Mars (2006) and its U.S. remake were both set in 1973 and named after a David Bowie song that came out that year. Since Spain was still a dictatorship in 1973, this version was set in 1977 - the year of the first democratic elections since the Spanish Civil War - and renamed after a song from the Spanish group Nacha Pop. The song came out in 1980, though.
When Sam travel to the 1970s at the beginning, the David Bowie's song "Life On Mars?" is replaced by Queen's "Bohemian Rhapsody".