Oh, I loved Goodbye Lenin! It has to be my second-favourite German film (after Lola Rennt, natürlich).
There are some quite poignant moments in it, I think, especially if you look at it from the view of the young people like Alex and Lara who grew up in the DDR, only for it to collapse around them just as they were on the cusp of adulthood. Basically they're told that everything they've been taught is obsolete and that they must become like the West - there are quite a few scenes like that. When Alex is trying to buy Spreewald pickles and the shop lady just laughs at him "Why would anyone want Spreewald pickles now communism is over?" or words to that effect; when they find the money his mother has hidden, too late and it is worthless paper when previously it was her life savings; when they buy the Trabant, which is basically a tiny inefficient engine on a paper-mache chassis, and the mother sees it as a sign they are moving up in the world when everybody else in Berlin now owns an Audi or BMW... lots of things like that.
Also you could go for the whole lies/deception angle and wax philosophical for a while. Maybe consider how similar the deception perpetrated by Alex on his mother, ostensibly to protect her, was to the deception and propaganda the DDR gave its citizens, to 'protect' them. Maybe the whole atmosphere of being asked to believe falsehoods in the DDR meant that she was able to believe the clearly ludicrous excuses for things Alex cooked up - like the Coca-Cola thing, and the astronaut being elected president. Or, maybe she didn't really believe it but went along anyway because of the ingrained peer pressure of a communist society?
Lots of potential in that film! If I hadn't already done my essays then maybe I'd choose to do one on Goodbye Lenin myself.