1. Where's My Water?
Swampy, the alligator who stars in Where's My Water?, lives in the sewer, a world of filth, and just wants to take a bath. His alligator brethren don't approve of his cleanliness, so they've sabotaged the water lines. Players help direct the water to Swampy's tub in a series of challenging puzzles. Swampy is cute and obsessed with his rubber ducky, and the quirky gameplay makes puzzlers want to play just one more level to find out what's next. ($0.99)
2. Mystery Ball
Mystery Ball is essentially a series of logic puzzles, each with a multitude of solutions. Players control FRED, a free range energy ball, as he works his way through a professor's experiment to cure his phobias. Players set up each world with doodads, tools that help FRED jump, corral his (oddly cute) enemies in one spot, and more. FRED collects bravery badges and conquers his fears through bright, engaging worlds that float effortlessly in the air. Both FRED and the professor like to talk to the player and throw in helpful hints, some of which might lead to solving the mystery. Since each level can have different solutions, it's even fun to play back through and find new ones.
3. Angry Birds
Love it or hate it, this list isn't complete without mention of Angry Birds. The huge iOS game success boasts several versions, in both paid and free varieties, and its audience seems to follow it wherever it goes. Players have to angle birds correctly in order to hit pigs that are stuck in different structures on each level. Who knew that flinging animals at each other was the recipe for an App Store hit? More importantly, why are these birds so angry? Angry Birds now comes in varieties like Angry Birds Rio and Angry Birds Seasons, and each installment is available in HD, too. ($0.99 paid version, Free versions available)
4. Cut the Rope: Experiments
Om Nom is the hungry little star of Cut the Rope: Experiments, a follow-up to the original Cut the Rope. Om Nom finds himself living with a scientist who's very interested in his obsession with candy. Cut the Rope's obejectives are simple: players cut ropes that are attached to Om Nom's precious candy, collect points and feed Om Nom. The bright, friendly levels keep Cut the Rope fun and light, and the new storyline adds more flavor to the game's straightforward concept. Players are quickly sucked in by the cute, quirky design and stay for the complicated logic puzzles.
5. Scribblenauts Remix
Scribblenauts was originally a Nintendo DS game. The Remix is the same game remade for iOS, packaged with some extra levels. It was a huge hit on DS and isn't doing so badly on iOS, either. Maxwell collects starites, and the player has to help him get them. The twist: the player writes in words, like "rabid squirrel," or maybe a simpler one like "ladder," and those objects appear on screen for Maxwell to use to reach the starite. The possibilities are only as limited as your imagination, which makes Scribblenauts hard to pass up in a world of repetitive games. ($4.99)