First up, love how clean and simple the website is, but I can't find a guide on how to update a game, that I've already downloaded in the past.

My situation:
I've downloaded [Dying Light 2] version 1.24.2 from rexagames. Since then, an update got released, so the current version you can download here is 1.25.4.
While the update didn't change anything groundbreaking, it provided small bugfixes, that I wish I could apply to my "old" version of the game.
(For other games, some updates could fix gamebreaking bugs!)

The whole game is nearly 60 GB large. It would be cool to have a small 100-500 MB update that we could download, instead of having to redownload the whole game.

This issue doesn't only affect DL2, but other large games too.

If there is a way on how to update a game, I would love to hear it.
(Can I grab an update from cs.rin? If yes, which one?)

But in general, please add an entry to the FAQ.

Since I create a new file from scratch whenever an update is released for games, I don't know if the updates or mod support actually work.
The update files you get from Rin are applicable for the RexaGames version but if you use a different crack as a result of the update files, your save files may be lost.
You can see which crack we used in the “Based On” section of the game topics. Save files match the Steam ID, which you can also see in the steam_settings/configs.user.ini file.

If you downloaded a Goldberg version game and the patch you applied uses a RUNE crack, you need to open the steam_emu.ini file and match the Steam ID with the Steam ID in the Goldberg crack. The default RexaGames Goldberg Steam ID is: 76561197960287777

Even if a 10MB update comes for the games they don't do it as a new file. They add a 10MB code into the 30GB file so I can't just update the games. To do this both the old and new versions of the game must be on your disk after that a patch must be prepared. I don't have enough storage space on my disk to keep the games I've added.