Here is the full list of all 6 Alien Hostage achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
You have completed 25 levels!
You have completed 15 levels!
You have died 20 times. Congrats on still being here!
You have completed 5 levels!
Good job.
Your first death. Don't rage just yet there is a lot more to see!