If any of you played Space Invaders Infinity Gene (and I'm sure that plenty of you did), then you'll know that it took the basic idea of Spacies and twisted it into something barely recognisable but brilliant. Groove Coaster didn't have the advantage of a classic framework to build on... so exactly what kind of game would it be?
You know what? You're right. I am cool.
It turns out that Groove Coaster is exactly what the name implies. Your avatar rides along a crazy track, looping and swooping in time to the music. At key points on the track, you have to tap the screen in time with the tune. Every time you're successful, you build and add to a chain, with perfect timing giving you a higher score. Miss a beat, and the chain is broken. Bye-bye, high score and S-Ranking!
So, Groove Coaster is a very simple game. But there's a lot to it, in the form of unlockables. For starters, each level has to be unlocked in turn. That's not exactly a problem or a hardship, by the way... it's just a natural progression. However; you can only play a level on Easy difficulty on your first attempt... there are Normal and Hard difficulty levels to be unlocked for every track.
Even completing a level doesn't mean you've done the best you can. Sneakily, the game has thrown in the ability to "ad-lib", an idea which has been pinched from Rock Band's "Freestyle" mode, unless I'm mistaken. To fully capitalise on this, you're going to need to have an understanding of the music, and of its beat. From this, you should be able to guess the points where extra notes could fit. Find them, and maximise your score. Guess wrong, and you could break your chain...
This adds an element of risk/reward to the game, although I'm not sure if I'm entirely comfortable with it. On the other hand, the game might be too easy without these... it's much harder to account for a player's timing issues when all the plyer has to do is tap the screen at the prompt (as opposed to "playing" the notes on plastic instruments).
Groove is in the heart.
As of the most recent update, the games has around twenty tunes, and with a minimum of three playthroughs of each one purely to complete every level, there's a good amount of game here. Even better, each level is short. That means that nothing outstays its welcome, and it's perfect for bite-sized, time-killer gaming. And the high-score element means you're always likely to want that elusive "one more go" that games developers are dying for you to need.
Groove Coaster is a lot more fun than it might have been. It has the odd frustration... occasionally, the shape of the coaster tricks you into thinking there's a beat when there isn't, and your chain is ruined. But even that can be overcome with experience. With high scores to be obtained for every level, avatars and skins to be unlocked and different difficulty levels to be beaten, this is a quality release. As of writing, Groove Coaster is 69p on iPhone/iPod Touch, and it's also 69p on the iPad. I think it's well worth that asking price.