Robo Defense seems really simple at the beginning. Armies march across the screen, and you take them out with gun installations. However, you quickly become addicted!

On one hand this is a fairly simple side scroller. You have a top down view of your map, and limited money as the troops start coming out of the left side of the screen, marching single-mindedly to the right. You want to keep them from reaching your base. So you set up a gun turret or two, and the turrets shoot the enemies. You get cash for that, so you can build more turrets. Then more waves come. Sometimes the enemies are faster, sometimes they are tougher to kill.

You find that the enemies go as straight-line as they can, so you begin to set up your turrets in a snaky maze-path so that the enemies have to go back and forth as much as possible before they get to the base. But then there are airplanes! Time to upgrade your turrets and add in some rockets.

Even if you get through the 100 levels of the first stage, there are then harder stages you unlock, which challenge you even more. If you're willing to pay for their full version, you even get more maps and additional stages.

I was wondering at first how much I would enjoy replaying this. After all, you figure out the maze-configuration, and it gets to be fairly straightforward. But once you get hooked into it, and moving up through the levels, you start eyeing those additional maps. Just what new challenges await? Heck, for $3, I *highly* recommend upgrading. Those these Robo Defense developers that we love what they've done and want to see more!

You can even buy upgrades with your winnings, and earn achievements for different types of high scoring activities.

I've played many awful games in my reviewing days, so I am not typically a person who adores everything. Both I and my boyfriend adore this game. If you haven't tried it yet, definitely download the free version and see what you're missing. You'll probably get hooked, and for $3, the full version is well worth it!