My game was stuck on 1.02 forever, and I had to manually find patches online to at least get to 1.10, but now that I have, I noticed Nithral just stands there not attacking, and thus can't die.

So I wanted to verify my cache, but if I try to "connect" on GOG Galaxy, it just doesn't... and without connecting, it keeps the "verify/repair" option grayed out, so I thought I'd try the website.

Logged in, clicked Library, sure enough Witcher 3 is in my collections, but I click it and it says "base game missing", which is clearly isn't!

Any ideas?!

Where did you buy the game? If you bought a key from a reseller, you should be aware that many stolen keys were sold and the games revoked. You should contact the store you bought the game from.

It was bought on Amazon. I've had the game for ages and played it through a couple of times, but I've never been able to get the game to update, presumably because I can't "Connect Now" on GOG Galaxy. It asks for a code to redeem, but aside a code for the arena game and the comic book, there's none other with the manuals.

So are you saying the game was previously on your GOG shelf and now it is not? If so, contact support.

You say can log into GOG, and the game is listed in your collection. You don't need to use Galaxy to update - just download the latest game, patch and DLC from your collection. Log into GOG, click Account and the game, which should be listed as :Witcher 3: Wild Hunt, the" You should have everything you need there.

It's possible your issues are from downloading dubious patches off the internet, so if I were you - I'd ensure to keep my savegames and download a fresh game, patch and DLC from your account.

[edit] - Sorry, I just looked at the pic you posted, so it seems my suggestions will be for naught. If you bought the hard copy version on Amazon, it should have a code on the back page of the manual, which you can redeem for a GOG code. If you have no code on the manual, then you may not have purchased what you thought you did and are most likely out of luck...

So I can't update my game, play the DLC, or even get past Nithral this time round? Super :(

You bought the game on Amazon. If the game is not as advertised, contact them and demand a replacement or your money back. This is assuming you haven't left it too late.