Defense Grid is rated E for everyone, and is a regular priced game for the arcade at 800 Microsoft Points ($10). The story is set in a future time in which aliens are again attempting to take over the world. They have been halted before by others, but now it is your turn to show them who’s boss. Followed by a friendly AI unit, you embark across several areas of this futuristic earth, fighting off waves and waves of these aliens (or buggers, as the AI calls them) and attempting to take back major cities and facilities. Yet, to stop them you must use an arsenal of different towers to kill the aliens before they reach the AI’s power cores, which are the only things keeping him alive and assisting you.

There is a decent variety of towers that you can use to your advantage.

• Gun towers – standard turret towers.
• Inferno towers – shoot out fire
• Laser towers – shoots out a laser that will damage the unit over time, even after it has left the laser’s range
• Temporal towers – slows enemies down
• Meteor towers – shoots meteors across the map will extremely high range and good damage
• Cannon towers – packs a lot of damage over a large area (it also targets flying units)
• Tesla towers – charge over time for more damage, but a slow fire rate
• Missile towers – are for air units only, but extremely effective
• Concussion towers – shoot out concussion explosives all around its radius to deal a constant amount of damage
• Command towers – increases resources and will reveal any stealth aliens.

Now, seeing how the whole point is to stop the aliens no matter what, you must place these towers in certain areas across the map. The only downside is that on some maps, you can’t place turrets where ever you want.  There are certain little areas of which a tower can be placed, sometimes its on the track itself or on the sides of the track.  This calls for more strategic turret placing to make sure the aliens can’t make it to your power cores. Though, in case they do, you have one last line of defense.  An orbital laser is available that will kill everything within it’s radius, but use this sparingly, because once you shoot it, it has a pretty long cool down time before it can be used again.

The game also applies a small side story during which the AI will explain certain things that have happened during his life (The AI is a former human who was ‘transferred’ into an AI), such as watching his son grow up, watching him die, and so on and so forth. It ties in with the main story and makes the game interesting to play, making you progress through the next part of the game just so you can hear what he is going to say next.

Defense Grid is a game I will never stop enjoying, as far as it being a tower defense game. A great time killer and a good game overall. A few touches of work could be done so far as with multiple voice dialogs, and maybe some different styles in challenges, but overall Defense Grid in my opinion will get a 9/10