The Talos Principle

This achievement is unlocked for reaching the top of The Tower and the associated ending. In order to do this, you'll first need to collect all green, yellow, and especially red sigils. Refer to Blessed Messenger (50G) for help with solving any puzzles.

Once you've collecting all sigils, head into The Tower and work your way to the top: on each floor, you'll need to use red sigils to solve a puzzle to open a door, giving you access to a normal puzzle within. Solving each normal puzzle grants you access to a computer terminal, which you can use to unlock the next floor above yours. To do so, most require a code, and that code is typically written in one of the three documents on that computer. Advance through each floor in this manner. Refer to THIS LINK if you need help at all along the way.

Once you complete Floor 5, you'll go outside and up a spiral staircase to the exterior platforms. Once you go through the purple barrier, you start an invisible timer. You now need to complete four floors of puzzles before the storm below you ascends and reaches you. You have a decent amount of time, but you are still under the gun to an extent. The puzzles are relatively linear though, since you'll be helping others along them who in turn help you. After you complete all four floors you'll reach a fan that launches you up into the clouds. Head up the stairs and interact with the terminal (note that here is where you can unlock Take It With You (30G) if you've unlocked Deal With The Deceiver (30G) on this save file) to complete the game and achieve this ending.