K: SF isn't bad, it just fails to be good. It's mundane, mediocre, in an age filled to the brim with shooters. There are some good ideas and some good mechanics there, but they aren't realized properly, to their full extent. There is some exploration to the map design, but none of it leads to anything. It's clearly a game made by a team trying to break from its mold, from their formula - that wasn't ever all that good, to begin with - but not quite achieving something. Also, the story is shit and the narrative is painful.
The multiplayer was fun, though. And the game is pretty.