There is no guide for this game yet. But apparently it is EASY POINTS! 

Exterminator - 10 points

Defeat the giant spider.

Sharp Shooter - 10 points

Don't waste more than 30% of your bullets.

Unstoppable - 10 points

Finish a zone without losing a life.

Lair Slayer - 10 points

Complete all underground zones.

Annihilator - 10 points

Kill more than 85% of the total enemies in a zone.

Small Arms Expert - 20 points

Finish a zone without using grenades or nukes.

Twin Medal - 20 points

Finish a zone in Co-op mode.

Speed Freak - 20 points

Finish a zone in less than 15 minutes.

Peace Maker - 20 points

Finish a zone killing less than 50% of the enemies.

Tricked Out - 20 points

Max out all of the vehicle power-ups.

Survivor - 20 points

Finish a zone killing 60% of the units on foot.

Assault Hero - 30 points

Complete the game.