: Ensure you have part1.rar , part2.rar , and any other numbered parts in the same directory .
: If lighting looks strange or portals aren't transparent, you may need to edit your autoexec.cfg file in the portal_rtx/cfg folder. Portal.with.RTX.part3.rar
100% Achievement Guide for Portal with RTX - Steam Community : Ensure you have part1
If you've already installed the game and are looking for a guide to complete it, here are the key resources: For a complete visual walkthrough of every test
Do you have of the RAR archive, or are you missing one of them?
For a complete visual walkthrough of every test chamber and the final boss, you can watch this guide: Portal With RTX Full Walkthrough (All Puzzles | DLSS 3) YouTube• 10 Dec 2022
: If you are using these files to play on a Steam Deck, common guides suggest extracting the files into a temporary folder and then moving them into the game's .trex directory (found via manage > browse local files on Steam) to replace existing files. Gameplay & Achievement Guides