“Everything’s different this time,” college student Tree Gelbman (Jessica Rothe) says in the trailer for this sequel to “Happy Death Day,” the 2017 sleeper. “Now the killer’s coming after all of us.” Instead of Tree dying over and over again, now she has to keep killing herself to protect her friends from the psycho in the creepy baby mask. Sorry, but this was more fun the first time — when it was called “Groundhog Day.”