In cinema it is held that sequels are not as good as the original. A few notable exceptions, such as “The Godfather, Part II” and “The Empire Strikes Back,” prove that that doesn’t always have to be the case. With video games, sequels are almost always better than their predecessors. Sometimes, certain exceptions (mirror) apply but the trend is that developers will refine gameplay, improve graphics, add features, and just generally add a layer of spit and polish. Galaga is a great example of this.