but two months since last blog post? (March 8)

March 18, but yes, it's been nearly seven weeks since then.

GOG's rolling out a new game submission form, with accompanying articles:
https://www.gog.com/submit-your-game
https://www.gog.com/blog/benefits-of-releasing-your-game-on-gog-a-guide-for-indie-game-developers/

But: If this is how GOG intends to conduct its business, and that's entirely their prerogative, I hope they at least solved whatever communication issues they've had in order to avoid situations like this one.

So basically don't call us, we'll call you...
And let me laugh at "GOG’s experienced PR and Communication Team"

Since the thread was necroed recently, I might as well mention this here, too:
The Store/catalog[ue] search page finally has the option to sort results by date added to the catalog again!
This is in addition to the fairly recent additions of filters for "DLC for games I own" and "games in my wishlist" (the latter likely meant to eventually replace the old wishlist, since that page has had broken functions for a while).
Another addition that been around for some months, but which is easy to miss (or forget about, like I did :P), is the ability to toggle many filters on the left-hand side between inclusive and exclusive mode by clicking the little eye button which appears to the right of a checkbox while you hover over it.
EDIT: "Left-hand side" & "to the right of the checkbox", not "right..." & "...right...".

Movies are gone from the Store menu at the top of the page. The old link still works for now, but only lists a total of 14 items. Thread: Where did the movies go?

Double Fine Adventure Definitive Edition is categorized as a game, while Road 96 and Lichtspeer documentaries are DLC.

This is such a mess that I don't know if there's any plan involved.

GOG is partnering with VaultN "to Offer Publishers Direct Entitlements via Retail and Channel Partners":
https://www.vaultn.com/vaultn-and-gog-team-up-to-offer-publishers-direct-entitlements-via-retail-and-channel-partners/

I take this to mean that publishers can make GOG games available from other places/stores, but not in the form of GOG keys that need to be redeemed.

I remember a few years ago GOG had announced something like this, claimable games without the need for keys, but then nothing came of it apparently.

There are some...

Ah interesting, I thought the games purchased on the Humble Store were simply keys.

We'll see what this new collaboration entails, GOG needs to spread alternative methods of buying its games to increase its brand visibility. Steam has also monopolized the market through the widespread distribution of their keys, not caring about the black markets that have arisen as a result of these policies.

The game cards of games that are on sale now show when the sale ends.

If the end of the sale is still a few days away the day and time will be shown (see screenshot 1) otherwise a timer counting down to the end will be shown (see screenshot 2).

I think that 'buy now' button is also new, unless it's just a while since I looked carefully at a catalogue page.

Yep, saw that one this afternoon for the first time.
Comes in handy for a 80% discount when I'm still thinking about the items in my shopping cart :)

Hm, I tried that but it doesn't work.
The new "buy now" button does not bypass your shopping cart (like it does for Insomnia sales).
Instead it's a shortcut for "add to cart" + "check out".

Argh!
Ok, so they made it worse.

It actually makes me sad about the wasted development time on this (planning, creating the graphic, adding it to the UI, functionality to hide when item is in basket and show when Item is not in basket + the functionality of the button itself), just to have the user do one less click.
We have so many more important mattes. If it would bypass the shopping cart, it would have been a good addition.