least-pozzed version for paranoid people

>go to their downloads page
>stop or delete whatever automatically downloads
>get the "unpacked" version (no installer, portable)
>extract it somewhere that doesn't require admin privileges, like desktop or documents
>move your Project Epoch folder into WhateverYouNamedTheExtractedFolder\resources\epoch_live, such that in the epoch_live folder you see the Project Epoch.exe, WTF, Interface, etc.
>create a .bat file and place it in the launcher folder next to Ascension Launcher.exe. this will it to run without admin privileges
set __COMPAT_LAYER=RUNASINVOKER
"Ascension Launcher.exe"
>run the Ascension launcher by using this .bat
>install Project Epoch via the launcher
>it will overwrite most things so desu you're not saving any download time, but it will preserve your configs, screens, addons, etc.
>go into epoch_live and clean out the Project Epoch.exe and the epoch_installer.exe. The one Ascension uses is Ascension.exe despite it still being Project Epoch and still appearing as such on its window title
>whenever the launcher updates, it creates another forced-admin .exe in a hidden folder named "tmp" and will prompt UAC by trying to execute that. you can either circumvent this by updating the launcher manually by redownloading it from the website and extracting+overwriting it into the same place, or create another .bat like the one above and place it in the tmp folder, changing the filename in quotes to whatever the filename of the updater .exe is (I forget)

Alternatively, you may be able to skip all of this in the future by downloading the Project Epoch files directly from their google drive link on the same downloads page (next to the 3.3.5 torrent link), but they haven't put them there yet.