The objective of Cosmic Invaders is to prevent the invaders from reaching the bottom of the screen. This is done by deploying defensive structures, accessible from the bottom right. Once deployed, towers will automatically fire on your enemies. Each costs money, which along with your remaining life is displayed in the bottom left. Towers can be sold, giving you back half of their original cost plus potentially valuable real estate, by selecting them with the left mouse button and clicking the demolish button. Right click cancels selection and placement. Pressing the escape key exits the game.

Laser turrets fire straight up every few seconds, dealing damage to the first invader the shot hits. Missile batteries fire seeking missiles at a slower rate, but they deal heavier damage, plus splash damage around them. The missiles explode if they fail to hit anything within a few seconds, although they still deal splash damage if they're close enough to anything when they do. Spark towers will deal heavy damage to a single invader, but have much shorter range.

This is a substantial update to a preview build released back in early 2007, under the same name. Towers can now be upgraded, and a boss encounter is thrown at you after every few levels to liven things up a little.

Name: Cosmic Invaders
Developer: X-G
Category: Strategy
Type: Freeware
Size: 1MB
Direct download link: Click here