The iPhone certainly has seen more than its fair share of physics-based block games, but none of them explode with cuteness and lovable personality quite like Tumbledrop. For a game that started out as a free flash demo, this brilliantly simple and intensely fun puzzle game couldn’t be possibly be any better suited for Apple’s portable touch-screen platform. Sending smiling little block creatures tumbling to their watery doom with a tap of your finger is a disarmingly cheerful task.

In Tumbledrop you must help a little pink star creature safely make his way from the very top of a precarious stack of yellow block critters to the bottom. This is done by tapping yellow blocks one at a time to make them disappear and gradually cause the whole stack to crumble. However, these living towers are surrounded by water, and ensuring the friendly star avoids making a splash is easier said than done – particularly when gravity and physics team up against you.

A stylish and youthful presentation packed with color is one of Tumbledrop‘s most attractive elements. The bright mix of yellows, pinks, warm blues and greens, and flashy rainbows stands out pretty starkly. Additionally, each block has eyes that blink and a mouth that moves on occasion. Aside from being absolutely adorable, this really adds a lot to the game’s overall charm, especially when the little fellows stop smiling and make mortified faces when they know they’re about to get soaked.

The game’s 60 levels are divided into three different tiers of difficulty. Early on you’ll only have to deal with a few blocks stacked up on a decent sized hunk of land, but harder levels throw towering spires loaded with many smaller blocks to contend with at you stacked across multiple small islands. Even if you blow through the main chunk of built-in stages, you can always wait for the new add-on levels that are currently in the works. There’s also a ton of replay value built into the game.

Beyond the sheer challenge of getting the pink star to land on terra firma, there are two special medals you can achieve in every level, and they both require you to approach the puzzles in a different way. Star medals are earned by accomplishing your goal within a limited number of moves, while heart medals are earned by clearing large numbers of blocks before dropping the pink star to safety. Both offer some compelling reasons to return to levels you’ve already completed and strive for perfection. There’s also a completely separate quick play mode that throws random levels at you and challenges you to beat as many of them as you can in a row without messing up.

The early 20-level PC version was deeply absorbing, and the developer has done an amazing job crunching that down into a portable format that’s equally enthralling and far more expansive without sacrificing any of the fun. Everything about Tumbledrop on iPhone left us impressed, and news of future level updates coming down the road is music to our ears. This is one adorable puzzle game, and a must have addition for your iPhone.