Apart from the beautiful soundtrack, the moment that hits you in the face during the course of the film is when the protagonist sees one of is closest friends in the corridors of the GDR offices. The subtext is that he's enrolled in the party in order to find work and in order to support his unborn child. The devastation on the face of the protagonist when he realises that his friend has given up the fight and his reaction to it is profoundly emotional; the protaganist hits his friend in the face and procees to hit him, not violently, just as though he's trying knock his old friend back into existence. They both end up sitting on the floor at the end of the corridor crying together in shock and frustration. The moment is poignant in that it highlights the constant battle not to take the easy route and be drawn into the system. That the collective fight is always easier than the fight alone. When the best friend has to put someone other than himself first he can no longer fight his own fight. The friendship forged on collective resistance is taken away and then protagonist is left without the support of his closest friend.
The feeling is generally one of humour, of lightness, that behind the Wall everywhere people were living their lives as their own, as anyone would. The final scene with a dance mob approaching the border control dancing to Dynamo 5's 'The Letter' suggests that music will help the fall of the Berlin Wall and suggests something about the transmission of ideals and support through songs and music; I'm thinking of Dylan, The Beatles, Springsteen, The Stones. This was how a generation expressed themselves as different to their elders around them and in union with the rest of their generation in the West.
I'm not saying that music brought down the Wall single-handedly, but it's expression of the cultural ideals of a generation certainly played their part. The Beatles are playing on the radio in my East German tenement flat just now. Power to the people!