Pulse is about beings who travel through Internet/cellular networks to attack people by taking their "will to live" (which I assume means "soul" in Hollywood).
I had the same problem with this movie that I've had with other modern ones. It seems like there's really cool special effects that go for great cheap scares, but it's weak on the plot. The first little bit is really good, the middle part drags and is just a series of cheap thrills, then the last part saves it from being "bad", in my opinion.
From a logical perspective, what's going on isn't explained very well and doesn't really make any sense. That's always unfortunate, since I always like finding out what's been happening.
I think this fails where a lot of horror movies fail: the being have no motivation. They just kill people, that's what they do, and they go for cheap thrills as they're doing it. For example, why would an evil being who wants to kill people for no discernible reason hide in a washing machine, throwing clothing on the floor until somebody walks up, then jump out and steal their soul (err, will to live)? It's cheap thrill and suspense, and adds nothing.
Overall, I'd give this a 5/10. It wasn't awful, but there was a lot I didn't like. Probably worth seeing if you're bored
