Here is the full list of all 7 Hunted achievements.
The base game contains 4 achievements, and there is 1 DLC pack containing 3 achievements.
Play the game for the first time
You know what you found
you got in then got out of your first space ship
You killed one of the final bosses (could be under main station or on a different one)
You found the Secret Final Boss Location
You visited the OS-200 Cave!