XIII
Cryostasis

Possibly ARMA but not sure if I would have liked them.

I might have liked some of the Telltale games but as I have never played any, I am unsure.

ADD: The Long Dark if it ever reaches a playable state here.

The only game I regret not buying, I believe it was just the 2005 game not the entire series. I ended up buying the entire series on disc a few years ago.

I own the ones I would really care about as far as I know. XIII, Cryostasis, Duke Nukem. I mostly only play RPG, FPS and point and click adventure games. I have the Telltale stuff I want from their site, DRM free.

Second Sight might be the only one I would have bought if I thought about it. Not sure if I even would have played it though, seems like more of a console style third-person adventure than something I'd be really into.

You must be frothing over the pending remaster later this year then, right?

Armello and Republique.

The Long Dark.

Telltale's Guardians of the Galaxy and République (that I can recall).

Telltale's Sam & Max games. I beat the first Sam & Max game recently and have been waiting for the new games to get a discount. Unfortunately, that did not happen before they were taken off.

Maybe in five to ten years I can download them as abandonware.

Severance: Blade of Darkness

It left before I became a regular here. That and XIII. Both of those are games I wish I had the chance to really get.

Duke Nukem Megaton Edition

They're still on Steam, so they're not abandonware. The new owners just wanted them off GOG I guess.

I have missed a lot of games on GOG which I would like to return, starting from TOCA Race Driver 3, Colin McRae Rally 2005 and Cryostasis, which already had been removed before I joined, up to Back To The Future, where I only realized lately that it has been removed.

Colin McRae
Chessmaster 8000
Second Sight
Severance Blade of Darkness
Dark Matter
XIII
Scratches
Arma series
TOCA Race Driver 3
ObsCure
Republique: The Revolution
Death Gate
The Long Dark
Operation Flashpoint
Armello

As far I know, there might be more :D. The one that I would've liked most is Chessmaster, I think and maybe Colin McRae, but those were gone before I even joined.

That was never here afaik.

Besides many titles already mentioned, TrickStyle and Re-Volt.

This is the whole list (taken from RWarehall's excellent spreadsheet)

10th Anniversary Collection I: The Timeless Essentials
10th Anniversary Collection II: The Art of Aging Gracefully
10th Anniversary Collection III: The Modern Classics
Achtung Panzer: Kharkov 1943
Arma 2: Combined Operations
Arma Gold Edition
Arma: Cold War Assault
Armello DRM Free Edition
Armello Original Soundtrack – Wyld's Call
Back to the Future: The Game
Ballads of Reemus, The: When the Bed Bites
Balls of Steel
Batman - The Telltale Series
Batman: The Enemy Within - The Telltale Series
Blade of Darkness
Chantelise – A Tale of Two Sisters
Chessmaster® 9000
Chronicles of Riddick: Assault on Dark Athena, The
Chronology
Colin McRae Rally 2005
Cryostasis
Dark Matter
Death Gate
Devil's Dare 悪魔の挑戦
Duke Nukem 1+2
Duke Nukem 3D Atomic Edition
Duke Nukem: Manhattan Project
Dyad
EARTHLOCK Hero Outfit Pack
Everything
F/A-18E Super Hornet
FEZ
FRACT OSC
Game of Thrones: A Telltale Games Series
Gray Matter
Gremlins, Inc.
Gremlins, Inc. - Astral Gamblers
Gremlins, Inc. - Automated Competitors
Gremlins, Inc. - Digital Artbook
Gremlins, Inc. - Original Soundtrack
Gremlins, Inc. - Uninvited Guests
Guilty Gear Isuka
Guilty Gear X2 #Reload
GWENT: OPEN PTR
Hector: Badge of Carnage
Hollow Knight Soundtrack Edition
Human Fall Flat
Industry Giant 2
Infinium Strike
Infinium Strike Demo
King Arthur's Gold
Lula: The Sexy Empire
Mark of the Ninja Special Edition
Mark of the Ninja Special Edition Upgrade
Marvel's Guardians of the Galaxy: The Telltale Series
MIND: Path to Thalamus Enhanced Edition
Minecraft Story Mode - Adventure Pass
Minecraft: Story Mode - A Telltale Game Series
Minecraft: Story Mode - Season Two
Mutant Mudds
Necropolis: Brutal Edition
Neverwinter Nights Diamond
ObsCure
Original War
Pathfinder: Kingmaker - Noble Edition
Perception
Pony Island
Prison Architect Name in Game DLC
Puzzle Agent
Puzzle Agent 2
Race Driver: GRID
Re-Volt
Real Myst
Recettear: An Item Shop's Tale
Republic: The Revolution
Republique
Republique Deluxe Edition
Republique Deluxe Edition Upgrade
Reservoir Dogs: Bloody Days
Reservoir Dogs: Bloody Days - Soundtrack
Rollercoaster Tycoon 3: Platinum!
Sam & Max Beyond Time and Space
Sam & Max Save the World
Sam & Max: The Devil’s Playhouse
Schein
Scratches Director's Cut
Second Sight
Simon the Sorcerer 4: Chaos Happens
Slender: The Arrival
Sokobond
Space Rangers
Star Control® Bundle
Startup Company
Stellaris: Nova Edition
Stellaris: Nova Edition Upgrade Pack
Strong Bad's Cool Game for Attractive People
Superfrog
Superfrog HD
Tales from the Borderlands
Tales of Monkey Island
TerraTech
TerraTech: Deluxe Edition
TerraTech: R&D Pack
The Long Dark
The Universim - DEMO
The Walking Dead: 400 Days
The Walking Dead: A New Frontier
The Walking Dead: Michonne - A Telltale Miniseries
The Walking Dead: Season 1
The Walking Dead: Season 2
The Walking Dead: The Final Season
TOCA Race Driver 3
TRI: Of Friendship and Madness
TrickStyle
UFO: Afterlight
Wallace & Gromit's Grand Adventures
War for the Overworld: Anniversary Collection
Wargame: European Escalation
Warsow
Windforge
Wolcen: Lords of Mayhem
Wolf Among Us, The
XIII