Destroy All Humans! 2

By completing Tunguska's storyline, you should have all available Odd Jobs open to you. From killing a Blisk Berserker that someone believes is a Yeti, to destroying the Blisk Base, and even lifting a certain doctor and transporting him all the way to the frozen outreaches, they're rather simple. The only one that would give you some troubles, since it did for me, would be the Yeti mission as the enemy is resilient and I didn't have any Bliskproof weapons by that time.