Robo Defense FREE is the lite version of a tower defense game available on the Android Market (the full version is also available for $2.99). It’s your run of the mill tower defense game; the object is to build units to defend your base from an onslaught of enemies both on land and in air. As you play you gain reward points which can be spent on upgrades, and achievements, which just make you feel good (and adds in-game bonuses!).

Once it’s downloaded, players can choose different difficulty levels (1-10 on the FREE version), and the only option for maps is the Basic one (others are included in the full version).

Those familiar with tower defense games will probably find the Level 1 difficulty pretty easy. The is quite a difference between Levels 1 and 2, so even experts might want to start off on 1, if nothing else just to see how the AI works. For levels 1 and 2, the AI is pretty simple. Mobs of guys, robots, airplanes, helicopters and tanks go in a straight line from their entrance point of your base. Building your tower line-up is a simple drag and drop process on the touchscreen. (I’d recommend the “maze” defense, forcing them to zig zag across the map to your base, that way they’re surrounded by towers)

The Gun costs $5 and works against land attacks. It can be upgraded to a Medium Gun for $4, a Flame Tower for $70 or an Antiair Cannon for $20. The Medium Gun can be upgraded to a Heavy Gun for $6.

The Slow Tower can be purchased for $10, and works against air and land, can be upgraded to an Upgraded Slow Tower for $10, Advanced Slow Tower for $10.

The Rocket Launcher tower can be upgraded to a Medium Rocket Launcher for $30, Mortar for $50, and Surface to Air Missile for $70.

Reward Points can be spent on different levels, for:

Stronger Bullets
Stronger Explosives
Faster Rocket Reload
Faster Antiair Relod
Faster Artillery Reload
Longer Flame Burn
Longer Slowdown
Health Reward
Starting Cash Reward
Unlock Teleport Tower
Unlock Mine Tower

All in the FREE version.

There are also options to Pause gameplay, accelerate enemy advancement (good if you have a lot of firepower and need some money) and Save games.

Robo Defense FREE should come with a warning that it’s highly addictive.

Robo Defense FREE (v1.2) is available in the Android Market under Games – Arcade & Action, or it can be downloaded by scanning the QR code below (must have Barcode Scanner on your Android phone). It’s 1.2MB in size, developed by Lupis Labs Software.