If you have a 5G (fifth generation) iPod then you are carrying in your pocket or purse a very capable machine.

Capable not just because it can play music, slide shows, and videos, and not because it can sync with your calendar and contacts, though doing so does make it very capable indeed.

No, the capability I'm referring to is the iPod's ability to play games. Not just some tired old solitaire or Atari 2600 wannabe 'Parachute' -- which are both only mildly more engrossing than watching fungus grow -- I'm talking about real games, stuff that is not only eye candy, but is fun, addictive, and a total waste of time (but you play them anyway).

When Steve Jobs announced that the iTunes Store would be offering games, I figured that the games offered would be stale rehashes of ancient arcade hits. Well, many of them are rehashes of old arcade hits, but updates for at least two games - Vortex, and Zuma- are anything but stale.

Vortex: Break-out with a bite

Way back in the day when there were more than 3 game consoles on the market for consumers to pick from, Atari offered the public the Jaguar, which sold poorly. One of the better games for the Jaguar was Tempest 2000, which also found its way onto other game platforms. Tempest was a fast and furious arcade shooter where targets crawled up a wall of these 3D shapes and you had to shoot them before they made it to the top. The perspective was as though you were looking into a well. It was a blast to play.

Another mainstay of the arcade era was Break-out. There must be a zillion variations of that ball and brick game, and every one that I've played was an excellent time waster.

Get those two games a motel room and the resulting offspring might look at lot like Vortex.

Vortex

As in Tempest 2000, the view of Vortex is as if you are looking down a well, but in this well, the walls are lined with blocks a la Break-out. At the rim of the well is your paddle. You launch your ball at the bricks in break-out style and rotate the paddle around the rim to keep the ball in play. Now add some power-ups, which can turn your paddle into a shooter, and suddenly things start to get real busy.

Vortex is a hoot to play and the control of the paddle is ideally suited for the scroll-wheel of the iPod. Lots of sounds, explosions, power-ups, and energetic fun keeps this little jewel on the top of your stuff-to-do-on-my-iPod-when-I'm-not-doing-anything list.

I have only two minor complaints: The first one deals with the music. I wonder how hard would it be to let the user play background music from a playlist of his own choosing while in the game? As it is, if you want to listen to your music you have to have your playlist set up and playing before you get into the game. Pressing the 'Play/Pause' icon on the scroll-wheel starts and stops music in your current playlist, and you can skip foward and back through songs as well using those icons on the scroll-wheel. But in order to change playlists you have to get out of the game altogether, which is a minor pain.

There's an 'Auto' and 'Off' setting in Votex and in Zuma that controls what music you'll hear while playing. As I mentioned earlier, you can listen to music from your playlist ONLY IF it is playing, but also only if the music option is set to either 'Auto' or 'Off'. 'Auto' will automatically play the game music if your playlist music isn't playing. 'Off' turns off the game music entirely. It's kind of an odd and confusing way to interact with your music and it could have been thought out more, in my opinion.

My other complaint is that, from time to time, the game hesitates. It's so brief that many might not notice it, but with a game like this one, smooth motion is a must. The fault may lie in my iPod and not the game software. Whatever the problem and where ever the cause, it's annoying, but not enough for me to stop playing.

Gimme Summa Zuma

Zuma is a lot like Bubble Trouble; you shoot colored marbles at a field of other colored marbles, match 3 or more of the same color and those marbles disappear. All the time, more marbles appear, making it harder to match and win. In Zuma, however, the field of marbles is in a sinewy line, the marbles slide forward towards a "golden skull," if they reach it you lose the round.

Zuma

The line of marbles adds a nice twist to a decent game, but the power-ups add a whole new dimension; certain marbles advance or delay the progression of the marbles in the line, others explode, one lets you pinpoint where your marble will go, and still others reverse the direction of the marbles altogether. It's addictive to say the least.

As you advance you'll find more marble tracks laid out in increasing complexity to deal with, and, of course, the marbles in the line move faster towards the skull.

You'll find that, as the game gets more frantic you'll wish you have a better controller; the click-wheel works great but at times I found that it wasn't precise enough. Maybe it was just me getting caught up in the game.

I have the same niggling complaint about playlists in Zuma as I had in Vortex, but that's about it.

I should mention that both games will look great on your 5G iPod; the colors are bright and clear, and the graphics fill the screen nicely, so very little eye-straining is required to play. Also, the instructions for the games can be found in iTunes in the 'iPod Games' folder.

So, there you go; two iPod games that I think are worth US$5 each.

The iPod as a gaming platform is an interesting concept, and one that could prove profitable for Apple and game makers alike. Vortex and Zuma do a good job in showing what's possible on Apple's music and video player, and I can hardly wait for other games to appear.