The story of Serial Experiments Lain has an interesting premise, and is accompanied by some nice animations, unfortunately the key points of that story end up being explained by characters towards the end rather than shown and unfolded in the plot. So the bulk of the experience consists of the viewer being dragged through a bunch of watered down episodes, only to then have the characters towards the end say, "Oh yeah, and here's what's going on." Showing, and not explaining, is pretty much the first rule of screenwriting. Apparently the writers didn't get the memo.
Review of Serial Experiments Lain
