It's been a little while since I have been on gog, I remember when you were on the store page for a game that there would be collections or suggestions of other games from other users. Does this still exist? Or has it moved?

Those were zapped a redesign or two ago.

You're referring to GOGMixes, which were removed with the redesign that hit a year ago. Not even left in a frozen state, not even sent in some form back to the creators if they wanted to keep their work and/or recreate it elsewhere, just zapped. At first they were saying that the new "collections", which were just some apparently sponsored catalog searches taking up front page space pointlessly, were going to be opened up for users as well in some manner, but that never happened either. Not that it'd have replaced mixes anyway, with no way to manually sort, add notes, show your ratings or make sure that only what you want shows up and not whatever else even an exact title search may produce.

The message their actions sent to consumers: we want social participation, but on our own terms that reveal personal data unless you're feverishly checking the page every day to be quick enough to opt out. Also, Facebook and Google are trustworthy partners...Really!

Additional messaging:
No to GOGmixes. But yes to video statistics (videos originally autoplaying when scrolled over) and profiles that are PUBLIC by default, including ability to find profiles by email address, and yes to listing number of games everywhere, including next to any review you make (they really seem to like doing this, for some reason).

So, I was gifted a title the other day, probably for recent purchases, and my spouse tried to collect it and couldn't.*
This is after trying to enter a recent competition (locate the hidden links on an email by solving riddles) which I also couldn't complete.

All the while this computer logs in without issue, but the second device is prevented (where it originally wasn't).

Additional additional message:
Rewards only for Facebook- and Google-centric participation.

Quite frankly, I could care less about some random entertainment that I have not personally chosen, so it doesn't matter to me. But I find it disturbing that the Googlification of the interwebs is slowly choking out any noncompliance to their world domination.
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* I have pop-ups disabled on this machine, so we use the iPad for entering the annoying authentication hoop-jumping nonsense.

Actually it was a user complaining the new *curated* collections if that's what you're on about which is different to GoG mixes?

I've been living under a rock these past years and so noticed some changes when I came back to look at what new stuff they have in store........

I thought the GoG mixes was a nice touch, like a community tagging feature akin to Steam's except much deeper as you could click on them and find out why they tagged them as such if they bothered to write a reason under the title. Why did they even remove it?

Edit: Ahh, found the post: October 2018.

NEvermind, found the answer: Apparently gogmix feature were never moderated or kept up to date with the site changes and layout...so they decided to delete it altogether.....

@Kolya2, thanks for asking and everyone else, thanks for answering.

I've been wondering the same thing. I rarely used the feature, but now that I'm somewhat catching up on my to-play list I was looking for that feature to point me towards other ones on GoG that were similar to the ones I'm in the mood for. Maybe I could dig something up on Archive.org, but probably easier to just hunt around a bit. The collections were nice because some games just get a lot more front-page time than others.

They went to say hello to the dodo.