With the Museum of the Moving Image about to start their six-week-long horror series, ”It’s Only a Movie,” which examines those recent directors who make up what has been termed recently (unbeknownst to me) the “Splat Pack” as well as their influential antecedents, we have a couple of new pieces on Reverse Shot that respond to growing trends in horror, from the lackadaisical slacker-hacker Severance to the grim pseudo-political 28 Weeks Later. Coming soon, some thoughts on Hostel Part Two, from the Splat Pack’s dubious eminence grise, Eli Roth.