Reviewing games is complex and time consuming. You have to play the game, make comparisons with similar titles, and then throw in a pinch of your own personal views on how enjoyable everything is.

Reviewing entertainment apps is easier and more functional as you focus on technical aspects such as features, user interface, and whether the app actually works. There's much less analysis of undefined things such as gameplay.

And that's my dilemma with Tune Runner.

It sits between being a game and an entertainment app, and despite consisting of both elements it's neither one or the other. That's its strength and its weakness.

Symbolic gestures

At least the gameplay is easy to explain. Tune Runner uses the music on your iPhone or iPod touch's library, although it also ships with some free tracks from Blink-182 offshoot Angels & Airwaves.

Select a tune and the game automatically does basic beat analysis and then you start. Your little boom box character called Groov-EE struts his stuff on the screen as a series of shapes scroll towards him as the music plays.

These are '7's, 'O's, 'Z's or a reversed 'V's shape you have to trace on the touchscreen as fast as you can to score points. They appear at tempo with the rhythm of the track, although as the beat analysis isn't sophisticated it feels a bit random.

Complete a tune without messing up too much and you gain a 5,000 point bonus. Even if you fail part way through the track, your score up to that point will be recorded and saved online via OpenFeint.

That's my tune

In this way, Tune Runner encourages a viral competitive spirit as you can see how many people have played each tune - there's also a top 100 list of the most popular tunes, which you can buy directly - as well as what their score is.

Because the game is so easy to play - just trace the symbols as fast as you can - it has an addictive quality that will have you playing until you've posted the highest scores on your favourite tracks.

As a game, however, there's little inherent enjoyment or skill involved. Of course, this makes sense in terms of encouraging as many people as possible to play, but it's disappointing compared to how other music games such as Tap Tap Revenge or Riddim Ribbon have approached the genre.

Cheap show

There's another reason Tune Runner is easy to play, though. It's a free-to-play game in which you have to buy battery packs in order to play more tunes once your original allocation is used up.

You can top up with a 40x pack for 99c or buy the game outright for $2.99/€2.39/£1.79.

The proposition seems to be working, albeit in the short term. But if Tune Runner has found early success as an entertainment app, it's difficult to recommend as a game. Strip out the music and there's little but your own competitive spirit powering the experience.