Here is the full list of all 18 HOSTLIGHT achievements.
Place your first Chauron.
Meet the Guide.
You didn't need to hear it twice.
Others aren't so lucky.
Find the Guide hidding.
He must be tired, but helped you with the mirror anyway.
Is this piece from another puzzle?
You managed to place the chauron even with the active shields.
You found the "slippery" Chauron.
The Guide unleashed its feelings.
You caught the Guide messing around.
The Guide redecorates the level.
Take a close look to the drawings.
Let the Guide finish the conversation while waiting on the Generator.
Defend yourself and defeat the menace.
Be comprehensive, don't achieve your ultimate goal.
You made it!, now enjoy your well earned rest.
Sometimes you have to try other ways to communicate.