The iPad has been waiting for a stand-out game, and we've been waiting for something to calm down our reviews editor ever since he ate a whole Sherbert Dib Dab - he's been running around with his coat on his head.

If this App of the Day can't mellow him, nothing can, and we'll have to call in the experts. Again. And by experts, we mean men with truncheons, obviously.

Thankfully, its blend of calming gameplay and soft ambient music should do the job...

Osmos HD

Format

iPad

Price

£2.99

Where

iTunes

Winner of several awards, the PC version of Osmos has garnered many fans. However, after a few plays of the iPad iteration and you wonder how it survived without a touchscreen all this time.

It's a cunningly simple concept: You start out as a middling-sized mote - a circular amoeba-like object that must eat smaller motes in order to grow. The landscape, though, is full of larger motes (more and more of them as levels progress) that can eat you, so you have to grow in size enough to dwarf them. It's a bit like the original organism section of EA's Spore, but there's one major difference...

In order to move around the screen, you must sacrifice some of your current mass, shooting small bubbles that propel you. The more bubbles you shoot, the faster you go, but the smaller you become. Additionally, if your bubbles hit other motes, they grow in size. Essentially, it's a case of softly going, rather than frantic action, and that's what makes Hemisphere Games' Osmos HD so compelling. It's an ambient, relaxing experience.

Naturally, later levels, which introduce other kinds of motes, such as antimatter versions which sap you of mass, and planetary objects that add gravity into the mix, become extremely tough. But, no matter how frustrating they become, the calming tones and music chills you out enough to smile through the pain.

It may not be for everyone - some may baulk at the distinct lack of exploding heads, for example - but they are morons. Osmos HD is THE game for the iPad right now. It's considerably less than the price of a one-way London tube journey, and infinitely less stressful. Essential.