With a grand total of one front-facing button and a touchscreen, gaming in the traditional sense is a challenge on the iPhone or iPod Touch. Fortunately, the promise of instant returns through the iTunes App Store and a widely available development kit have encouraged creativity and led to many innovative time wasters. Unsurprisingly, given the iPhone’s touchscreen interface, and the limited periods of time people have to play, many of the best games are puzzle-based.

Enigmo (Pangea; $0.99) is a puzzle game that takes full advantage of the iPhone’s graphical capabilities to deliver engaging problems based on physics, or at least something resembling it. Like the classic game Lemmings, you need to get something from point A to point B. Except this time, rather than allegedly suicidal rodents, you need to get water, fireballs, and later a green goo from the dispenser to a bucket. To accomplish this feat, you’re given springs, sponges, and metal beams to reroute your target fluid. Starting with simple tests that require only a single spring and some skillful aim, you’ll quickly need to construct elaborate contraptions, banking the “fluids” off of existing structures, if you’re going to be successful. If you’re not careful, you’ll quickly find this a productivity killer as the hours get washed away by water drops and balls of fire.

With an exceptional attention to detail and a great artistic feel, newcomer Touch Physics (Gamez 4 Touch; $2.99) has quickly climbed to the top of the App Store’s paid list. The object of this game is quite simple: you’ve got a ball, and you need to get it to a star. In this colourful game, you accomplish this by drawing objects with your “crayon” (your finger) to help the ball get to the star. Other than the law of gravity, there are very few rules. You can draw beams that will cover holes, or can even be used as levers or seesaws to launch your ball over gaps. You can draw masses to push the ball, or blocks to stop it from rolling into the abyss. The objects behave in a remarkably realistic fashion, and provide a virtually unlimited amount of ways for you to solve the puzzle. Like Enigmo, the game is addictive, and a fantastic value.

Although the lack of buttons and raw processing power keeps the iPhone out of direct competition with portable gaming platforms like the PlayStation Portable, its innovative puzzle games provide a remarkably engaging experience.