Welcome to this week’s edition of iPhone Gems! Once again, we have three completely different games to showcase this time out, including a driving game from Electronic Arts, an overhead shooter originally released in arcades in 1999 by Psikyo, and a hack-and-slash zombie game from Bulkypix. One of the titles is much better than the others, even when its higher price is taken into consideration. Our pick of the week is EA’s Need For Speed…