The combat knife is an effective close range weapon, and it is also your starting weapon in Earth Taken 2. Use it to break through wooden barriers and cut through enemies. The coolest thing about the knife is when you sneak up behind an enemy, or get close enough, you can do a stealth kill move that will instantly get rid of your foe. Awesome stuff.
VicariousE
Sounds like an awesome addition! Did you update the author description and the walkthrough in-game as well?
SeethingSwarm
Thanks! ...I'm not sure what you mean, This is a new weapon for the upcoming sequel. It's not a new weapon for Earth Taken 1.