Crash Birds Islands

"Free as a bird", sang John Lennon. Little did he know that some 30 years after his passing people would have enslaved avian kind for their own wicked amusement.

Well, digitally at least. In addition to pinging birds into brick walls and dropping chickens into deadly killing machines, it's now possible to steer gulls through rudimentary obstacle courses.

Crash Birds Islands proves that when it comes to modern iOS games, birds are far from free - in any sense of the word.

This kid-friendly flight sim has you steering a gull through a series of sharp and colourful 3D levels, tilting your iPhone or iPad to direct its flight path.

You must reach the level-end - which is marked by a giant spinning windmill - within the strict time limit, but it's the acrobatic feats in-between that make things interesting.

You're assigned various tasks to complete along the way, such as knocking over a bunch of portaloos (yes, really) or flying through hoops. The speed with which you achieve these determines the star rating you'll be awarded at the end of each stage, and therein lies a fair amount of fun.

Alas, this is where Crash Birds Islands's (is it just me who finds that a mouthful?) irritating in-app purchase system rears its head.

It's impossible to achieve more than a one-star rating on any of these levels - even the tutorials - unless you upgrade to a speedier gull.

Guess what? These gulls cost a lot more than the meagre amount you have at the outset - or can hope to accumulate through a reasonable amount of play. Essentially, if you want to achieve more than the bare minimum here you have to pay out for a chunk of digital currency.

This wouldn't be so bad, but when items you need to tackle certain courses - such as the rocket pack, without which you can't smash through boxes - also cost you some of this same currency, it can only end in annoyance.

If Crash Birds Islands were a free download we could understand this stingy approach. The core game would essentially be a limited Trial mode. But it's not. It's a paid app.

Despite being a perfectly pleasant and attractive casual flight game, Crash Birds Islands's effective refusal to let you play chunks of the game without paying extra means we can't recommend it unreservedly. This bird needs to be free.