Welcome to this week’s first gaming edition of iPhone Gems! In a separate earlier review today, we covered the impressive Plants vs. Zombies from PopCap Games, but we still had four other titles we wanted to share with you in this roundup. One’s an overhead shooter, another’s a puzzler, the third is a cooking game, and the fourth is a snowboarding title. Our top picks of the bunch are Cogs and X2 Snowboarding, but all four of the…