"Chain Letter" is a nonsensical, bloody mess that, well, is missing a few links.
Great-looking teens supposedly living in Silicon Valley fail to forward an e-mail or text threatening death, and guess what? They die. In hilariously over-complicated ways involving an actual chain.
Genre movies rely on their rules. Once those are ignored, they just become boring free-for-alls, killing time until the next drawn-out stalk-and-murder scene. So it's a problem that this killer is only sort of a Luddite who sort of targets people using technology if they sort of fail to send his chain letter to (about) five people within 24 hours … sort of. Some characters send it to many, some to none, some die within seconds, some days later. In the meantime, there's plenty of hyperactive sound design and much jumping out of cupboards.
There are evidently no parents in this kingdom of photogenic mid- to late 20s actors cast as teenagers — until they pop up as storytelling cheats. It's too much to expect relationships among characters, but these cardboard cutouts simply don't behave as humans do. The logical gaps and gaffes mute any fun bloodthirsty viewers might have derived from witnessing the comically elaborate slaughters.