For those of you not familiar with this style of game, you have a gun that looks out over a track. Along the track will move coloured marbles, and your single shot gun will be loaded with similar marbles. Move the turret to fire the marbles, and if your shot results in three or more marbles of the same colour touching in the track (your target marble pushes into the line), then boom! Those marbles disappear, and everything else closes up. Smart players can get a chain reaction set up as more and more colours close up on each other – which is where you can start piling up the points.
This mobile version, working on a much smaller screen, has made some compromises to the gameplay, the main one being that instead of a spinning turret, your gun moves along the edges of the screen. This also means that the path of your thrown marble isn't at some strange angle, but generally either horizontally or vertically around the screen.
As the levels progress, the tracks that the long line of marbles follows get ever more complicated, including more twists (shielding the rear of the line from your gun), underground tunnels to other parts of the screen, and of course the end of the line – once the marbles (which never stop moving) hit that, it's game over. You either clear all the marbles or you're going to die a horrible arcade'y death.
This being a java-based title (and you wouldn't know it from the speed and smoothness on display here), controlling your gun is from the d-pad (or the 2, 4, 6 and 8 keys). Two of these will move the gun from side to side, depending if you are on the top and bottom, or left and right of the screen, and the direction that points into the gaming area will fire the marble. The opposite direction will flip you to the opposite side of the screen (a nice gameplay twist), which may be needed to get some strategically placed marbles into the line.
If you don't make a set that explodes with your fired marble, it will be added to the line, lengthening it and either getting an awkward colour in your way, or (after you've played for a while) help you set up a chain reaction later in the game – thankfully you get a note of the next few marbles coming up to you on the bar at the bottom of the screen.
Zum Zum is a lovely little game. It's colourful enough to make it clear on the screen of my N95, and the smaller game area means shorter games, but with just as much panic as on larger scaled versions. The controls are simple enough, and the quick flipping to the other side of the screen, while sometimes meaning you 'flip' instead of 'gun', adds a nice level of strategy to go with the continually changing nature of the game, thanks to the random distribution of colours.
There are lots of levels and extra add ons, such as exploding marbles to clear lots of unmatched marbles in the lines, laser sights and pause icons which you can trigger with combinations that ultimately keep the game fresh, even though you are in your hundredth queue of the month. Zum Zum is what mobile gaming should be about – a well implemented idea that plays in short bursts, with just enough addictiveness to keep you coming back.
-- Ewan Spence, July 2009.