An indie darling since its original release in 2008, World of Goo has reaped more plaudits than we can count over the years. And although the iPad and iPhone versions aren't hugely different from what originally came out on PC, they deserve everyone's rapt attention.
In World of Goo, you have to suck-up balls of black goo (think drops of tar) into the World of Goo Corporation, which turns them into various products. Sounds like you're the bad guy, right?
In each level there's a vacuum pump to suck them up, and you have to help them get there. You drag across the screen to manipulate the balls of goo, and should you place one near enough to another, they'll link together letting you form structures. World of Goo is a top demonstrator of what's so great about physics gaming, though, and you can only put so much pressure on these structures before they all apart.
Matching the easy-going style of casual games with the intelligence of a more substantial puzzler, it satisfies on multiple levels. It's cute and colourful - jolly, even - but this acts as a handy layer of accessibility to sugar-coat its supremely intelligent design. In the later levels, a degree in bridge building would come in handy here. But World of Goo has a physics engine solid enough to let you know it's your fault whenever you fail.
The indie classic comes to iOS, and benefits hugely from the tactile interfaces of iOS devices.