Although it doesn’t reinvent the wheel, “Life” has an intriguing science-fiction premise and just the right actors to carry it through. So what could go wrong? Plenty, as it turns out. Jake Gyllenhaal, Ryan Reynolds and a group of astronauts find a life form on Mars that could provide enough evidence for extraterrestrial life. But is it as innocent as it appears to be? If you’ve seen enough movies (and I’m sure you have), then you probably know the answer to that question. Suffices to say that writers Rhett Reese and Paul Wernick (who borrow a lot from “Alien” and other successful science-fiction movies) play it safe, perhaps a bit too safe. The result isn’t completely terrible, but it isn’t memorable either. The best thing I can probably say about “Life” is that it looks great, and Director Daniel Espinosa makes the most of his spectacular sets and directs his actors with confidence. But a good cast and eye-popping special effects cannot save a movie without a good third act or a solid conclusion, and that’s where the movie falls short.