Carcophony is an interesting puzzle/strategy game with surprising depth for an indie game
The concept is dead simple, keep the flow of traffic moving by turning the traffic lights to green at the relevant junctions. It starts easily enough, but then things get more tricky - the flow of cars is relentless, and leave them waiting at the lights too long and it's game over. Add in other distractions such as ambulances requiring a clear route to get to their destination in time, and the action can start to get quite hectic.
BUT - you've got to give it time. Play it for five minutes and you may be left thinking there's nothing to it. But when you start realising the points bonuses on offer for chaining cars of the same colour, extra layers of strategy and tactics will start to emerge. In the end, you start to plan your moves well in advance in a similar way to how you might in games such as Tetris, leaving things to the last possible second like detonating a gate for maximum points in Geometry Wars.
Overall the game has very high production values for an indie game, with features such as multiplayer modes and online scoreboards, which add that extra dimension to competitive gameplay with your mates (although a Gold account is required for online score sharing). The graphics are simple but highly effective, and the music changes as you progress through the waves of cars.
In summary, this is one of the most addictive and polished games on the indie marketplace and I would highly recommend it. The longer you play it, the more it will reward you.