Here is the full list of all 15 Portal with RTX achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Earn gold medals on all Portal challenges.
Earn silver medals on all Portal challenges.
Complete Portal.
Beat all six Portal advanced maps.
Earn bronze medals on all Portal challenges.
Beat four Portal advanced maps.
Beat two Portal advanced maps.
Fall 30,000 feet.
Knock down a turret with another turret.
Do whatever it takes to survive.
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Make the correct party escort submission position decision.
Jump 300 feet.
Acquire the fully powered Aperture Science Handheld Portal Device.
Detach security cameras from the walls.