Finally watched this movie last night, I certainly enjoyed it but had to stretch my suspension of disbelief to breaking point to do so.
They lost a lot of points with the whole ‘omfg! people only use 1% of the brain’ nonsense, the ‘humans as batteries’ conceit seems to make a lot of people hate The Matrix but this line is just as bad.
One thing is they never really explain the ‘dream-access’ technology, as far as I could figure it is that its actually a form of virtual reality that can only be utilised on unconcious minds, a form of technologically induced lucid dreaming. This would explain how ‘dreams’ can be designed and built, they’re just complex programs, which the unconcious human mind uses as a basis to build the dreamers reality around. In addition this would explain the time slow-down effect as they go into deeper levels and realities, it takes substantially more processing power to add the extra complexity, as the human mind allied to the computer processes are working so much harder more information is being passed through in a given moment and subjective reality slows down.
Another point is that I had difficulty seeing the main character and the other members of the team as heroic or even sympathetic as we were apparently supposed to, the basic plot is based on a plan to effectively rape an innocent persons mind and one who did come across as sympathetic.
Yes, I am overthinking this, why do you ask?