I just read the Giant Bomb review and the 3/5 review seems pretty bs to me. Giant Bomb made the statement that the single player while sometimes being entertaining isn't very good throughout, but during the very short time they're talking about multiplayer, they throw praise at it except for one small issue. It got me thinking, so I looked up their Battlefield 4 review. 4/5. Short and crappy single player, issues with the multiplayer but good multiplayer nonetheless.
So Battlefield gets a pass because it's known that the previous game delivered an absolute shit storyline, but they throw far more weight towards Killzone's campaign? This isn't really specifically about Killzone, it's how gaming sites allow biased reviews like this to be published. If you're going to score against one game, you should score against the other game for the exact same issue. Different reviewers, but they're getting paid as that specific company and should be held up to the same basic standards. If the campaign matters here, then it should also matter here, if it doesn't matter here, then shouldn't matter here. Looks like bias to me.
*edit*
Doing further research and reading Jeff Gertsmann's Killzone 3 review shows further proof of how biased the review is. The first four paragraphs of Killzone 3 are about the story and how disappointing it is, with six more paragraphs detailing the multiplayer. Both games have disappointing story, both games have great multiiplayer, but the Shadow Fall review is incredibly half assed and in two paragraphs of talking about muliplayer, the only thing that is said is that it's good and that there's an issue about your loadouts when there are restrictions due to the custom warzones, requiring you to set your load outs up for that specific warzone. The review doesn't go into any other detail about the multiplayer. Nothing detailing how the challenges for each weapon work, nothing detailing the perks like they did with Killzone 3. It's like his review has some sort of hidden agenda so he just threw it up and called it a day.