Based on Williams' 1981 arcade game (which is also known as Stargate), Defender II for the NES is lacking several features of its coin-op cousin, most notably Inviso and Hyperspace. Strangely, when you rescue a resident (humanoid), it is no longer necessary to return him or her to the planet's surface, making the game easier than the original. One thing the NES game does add is an introductory musical score, which purists will scoff at. Despite these setbacks, basic gameplay does retain some enjoyment, thanks to smooth scrolling, faithful graphics and the inherent greatness of the Defender formula.