The movie was ultimately a 7/10. The overarching plot ties back to the idea of inherited sin - a family "curse" that is handed down through generations with each new generation forced to fulfill it. The family seems to know that they live in sin, as was exhibited by the saint statue in the alcove at the top of the stairs being turned to face the wall.
The only point that left me confused was whether or not each new generation was meant to be a perfect copy of the previous one. There are several pictures through out the movie that seem to be identical to the main characters, but represent their ancestors. There is also the repeated line coming from the 'Lodgers' "Secure our immortality." This is said each time the characters are pushed to consummate.