Full list of all 12 Back In 1995 achievements worth 1,000 gamerscore. It takes around 1-2 hours to unlock all of the achievements on Xbox One.
Clear the opening sequence.
Clear the first stage.
Clear the second stage.
Clear the third stage.
Clear the fourth stage.
Complete game with first ending.
Complete game with second ending.
Get the pipewrench.
Get the shotgun.
Get the pistol.
Get the flashlight.
Collect Dr. Randell newsclips.