6. It Destroys The Logic Of The First Film - Terminator 2: Judgement Day
The general rule of a good sequel is that it takes what worked from the original, but presents it in a new form, providing something related and also original. Terminator 2: Judgement Day certainly does that, using the same basic idea as the first one, but with some key twists. And yet in doing so it also blows open the tight logic of the original, setting the series on the spiral towards narrative confusion it's been on ever since. The Terminator is at its heart a Grandfather paradox. Skynet sends a robot back in time to kill Sarah Connor. Kyle Reese goes back, stops the robot and impregnates Sarah, providing the whole reason for time travelling in the first place. It's a delightful time loop that makes one of the definitive action movies of the eighties all about love. The sequel takes that plot, but uses a totally different form of time travel; instead of everything being predetermined, the future can be changed, leading to a mid-film detour to actually avert the machine apocalypse. It's a great idea that provides an incredible plot force to the movie, but there's no escaping that it renders the ending of The Terminator a little weak.
