New games:

Concubine
Undercover with Nora

New game, edition and DLCs:

HOTEL BARCELONA
HOTEL BARCELONA - The Jukebox
HOTEL BARCELONA - Late Check-Out DLC: From Dusk Valley to Grandall Estate
HOTEL BARCELONA (Original Game Soundtrack)

EDIT: The news post with interview about HOTEL BARCELONA base game showed up a couple of days later.

...

Oh you're fast! I wonder if they'll have an announcement in the morning for this sudden midnight gmt/1am cest release?

edit: oop they did not

edit the second: five days after release: https://www.gog.com/en/news/release_hotel_barcelona_read_interview_with_one_of_the_creators

I hope someone at least fixes the broken link to https://www.gog.com/forum/hotel_barcelona

This is a very nice surprise, anyway. Hopefully it won't be the last White Owls game to appear on GOG.

New game:

Terrinoth®: Heroes of Descent

EDIT: The news post showed up a while later.

New game:

Chef Knight

New game, edition and DLCs:

Mutants Ate My Carrots
Mutants Ate My Carrots Deluxe Edition
Mutants Ate My Carrots - Animalies Comic Book
Mutants Ate My Carrots - Sketchbook
Mutants Ate My Carrots Soundtrack

New game and DLC:

BoneCraft
BoneCraft - The Race to AmadollaHo

New edition:

Rain World - Complete Edition

New bundles:

Akupara Deckbuilding Cat Duo
Akupara Hidden Gems
Akupara Multi-Sided Monsters
Akupara Slice of Life Bundle
Darkside Detective - Series Edition
Evolve or Perish
Heart of the Dice Bundle
Heartfelt Homes Bundle
Hunt or Hunted Bundle
Jeremy Couillard Collection
Macabre Mysteries
Pixeljam x Akupara

New bundle, editions and DLC (not mentioned in this post):

Ecstatica I + Ecstatica II
Ecstatica Deluxe
Ecstatica II Deluxe
Ecstatica II - 8K pre-rendered backgrounds

You'll live to see porn parody video games of video games.

The first game also has a pre-rendered background DLC: https://www.gog.com/en/game/ecstatica_8k_prerendered_backgrounds

Of course it has, but it's already mentioned in the news post on the right hand side panel, thus it isn't unannounced.