I (almost) thoroughly enjoyed the campaign. Kind of a throwback to a time when shooters didn't rely on shallow scripted set-pieces so much. I was particularly impressed by the implementation of all the non-standard gameplay elements. Neither the owl nor the echolocation device have been thrown in just because they were fun to use and looked neat. I felt they were absolutely necessary, especially later on. After all, the Helghast are quite hardy, and if even a single one of them manages to flank you undetected it's usually lights-out for poor Lucas.
Heck, even the story wasn't all bad. I'm okay with a bit of hamminess in the delivery of your message as long as you're at least saying something. Also, Echo is a very cool character. Give her the next game, please.