Metroid is good but flawed. It looks good, sounds good, and plays well, but the core of the exploration (its key element) is hindered by its technological limitations. Too much time is spent away from the gameplay making maps, taking notes, and bombing or shooting every surface on every screen just to move forward. If you opt to use a walkthrough, then you lose that element of exploration. In 1986, it was revolutionary, but it's hardly worth playing today. Play Zero Mission instead.