Here is the full list of all 20 Relive achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Confirmed... to be your best friend!
Complete the first Story level
Complete the second Story level
Complete the third Story level
Complete the fourth Story level
Find all secrets in the first Story level
Find all secrets in the second Story level
Find all secrets in the third Story level
Find all secrets in the fourth Story level
Find all secrets in all levels
Launch a training session
Stay a while and listen
Save the Devs from certain death :D
At least they didn't fall out of my pocket
The old school way
You wouldn't download a martian AI
This stuff works IRL!
Not as bloody as you expected
Don't be sad!
Yeah, no problem, it's not like you are all going to die or something!