The Dark Knight - [spoilers ahead, ye be warned]

[Alex]

Yes, it has to be clear on its first viewing. But that does not mean that everything has to be fully appreciable on its first viewing. At least not to me.

For me, The Dark Knight was completely clear on its first viewing (though I'll admit that some things may be poorly edited) but I suspect there'll be readings of lines, specific set ups, minor events, that will only carry their fullest weight when rewatching them with full knowledge of the events that follow.

Just a crude example would be The Sixth Sense where everything made perfect sense watching it the first time, but on later viewings a lot of missed things of significance became apparent.