Here is the full list of all 27 8DAYS achievements worth 1,000 gamerscore.
Win one game
Rice War is over
Follow the light dude!!!
Now things get interesting
It's dangerous to go alone, take this
No pain, no gain!
So long and thanks for all the fish
Second miniboss defeated
One potato, two potatoes, three potatoes...
The power grid is safe!
Have you played HassleHeart?
This story began centuries ago
Shogun of Takezo Doraku, killed by G.O.D
Enjoy your journey
Video games are not evil
Dog watcher defeated
Find the sniper rifle
Survive the journey across the temple
What has just happened?
G.O.D. boss defeated
You are entering Santa Clara Games headquarters
... to bring peace to the world
Takezo's path of revenge has come to an end
Who controls the media?
Lola's mission comes to an end
Mike's mission comes to an end
Takezo's Path of Revenge achieved