Episode five of Secret Invasion gives me a good idea of why viewers and fans were so mad about this series because you don't necessary need to be a hard core fan to get to that conclusion, things really pick up a pace here and it was just too fast, the series at least might need another two episodes so it doesn't feel that way, things did happen but they were closing matters scene after scene, probably concluding things just too fast.

Source Until Episode Two I don't see why Secret Invasion got so many bad reviews although considering how it did episode by episode on IMDB I'm probably soon to find out and already have that hunch that