Alternate cover edition can be found here.

The military sci-fi classic in a striking new package

Felix is an Earth soldier, encased in special body armor designed to withstand Earth's most implacable enemy-a bioengineered, insectoid alien horde. But Felix is also equipped with internal mechanisms that enable him, and his fellow soldiers, to survive battle situations that would destroy a man's mind.

This is a remarkable novel of the horror, the courage, and the aftermath of combat--and how the strength of the human spirit can be the greatest armor of all.

(From Goodreads)