Oh man, there are so many great games if you're willing to play old stuff (although it looks like the summer sale is over):

Still on Sale

• System Shock (remake)
• Psychonauts 2
• Myst 25th Anniversary Collection
• Death Road to Canada
• Alan Wake
• Alan Wake's New Nightmare
• Project Zomboid

Classics

• Jazz Jackrabbit Collection
• Jazz Jackrabbit 2 Collection
• Contra Anniversary Collection
• System Shock: Enhanced Edition-
• System Shock 2
• Grim Fandango Remastered (I can't recommend this one enough; best game ever)
• Mortal Kombat 1+2+3
• The Settlers 2: Gold Edition (this one is also fantastic)
• Theme Hospital
• Dungeon Keeper Gold
• Dungeon Keeper 2
• SimCity 2000 Special Edition
• SimCity 3000 Unlimited
• SimCity 4 Deluxe Edition

I love RimWorld, and I love DRM-free, but RimWorld on GoG is a mistake.

Instead, buy RimWorld directly from Ludeon. Then you get both DRM-free files from them (to enjoy in the fallout bunker), AND a steam key (so that you can easily enjoy the metric boatloads of modding content on the steam workshop).

Oh my gosh, if you like Metroidvania stuff, play Ori and the Blind Forest!

I literally just posted about a few of these in another thread. :)

Decent: Freespace and Freespace 2 are the best Space Fighter - Dog-Fighting Tactics games I've played. They still hold up to this day. And the voice-acting is great.

Dungeon Keeper and Dungeon Keeper 2 are also solid games, although more in the silly corner. Dig out a dungeon, build rooms to attracts creatures of the dark, train them and go to war against the foul knights and kings of the overworld.

The OG Fallout games are always worth a mention. Fallout and Fallout 2.

If you're into old disturbing point and click puzzle games Sanitarium is a classic.

Or a bit more laid-back storytelling with mysteries, maybe? Then Oxenfree is worth looking into.

In the FPS category I recommend the Metro games. Well, the two first ones anyway. Metro 2033 and Metro: Last Light. Stealth is optional, but advised. :p

I'd also be amiss not to mention Soma. It's a scary game and a solid mindfuck at the same time. Approach with caution.

That's my list for now. I hope there's something in there you can use. :)

Loom is one of the greatest games of all time, I'll die on that hill. Such a shame the sequels never materialized.

Baldur's Gate 1 and 2 enhanced editions. Several hundred hours of quality RPG. Bought them several times already

If you’re a fan of Star Trek, they have quite a few excellent titles. Personal favs are Armada II (RTS), Bridge Commander (Ship Sim, even better with mods!), and Elite Force (you’re a Security officer on Voyager, FPS made by the Quake developers.

You can usually pick up Terraria when it's on sale for about $5. I haven't played it in forever but I enjoyed it at the time and apparently it's only improved since.

gog isn't my main platform for games (mainly because there's no good support for steamdeck) but some games I've played that I liked are:

• A hat in time 3D platformer
• FAR Lone Sails Vehicle adventure
• Firewatch Walking sim
• Frostpunk City sim survival
• Ghostrunner Cyberpunk first person parkour slasher
• Gris Beautiful 2D puzzle platformer
• Gorogoa Beautifully illustrated and imaginative puzzles
• Hellblade Dark fantasy action
• Night in the woods 2D platform adventure
• Oxenfree Supernatural thriller adventure
• What Remains of Edith Finch Walking sim

Some of the most popular games are on GOG - Tomb Raider (classic) series, Prince of Persia series, Baldur's Gate series, The Elder Scrolls series (including Skyrim) and several others. Modern titles apart from The Witcher series and Cyberpunk 2077 include Horizon Zero Dawn, A Plague Tale, Disco Elysium and Psychonauts 2. But perhaps the best known titles on GOG are indie platformers like Hollow Knight, Ori and the Blind Forest and Terraria.

Blackwell Bundle
When Rosa Blackwell’s only relative dies after twenty years in a coma, she thinks the worst is over. This all changes when Joey Mallone, a sardonic ghost from the 1930s, blows into her life and tells her that she is a medium. Whether they like it or not, it is up to them to cure the supernatural ills of New York in this critically-acclaimed series of point-and-click adventure games.

GRIS
A serene and evocative experience, free of danger, frustration or death. Players will explore a meticulously designed world brought to life with delicate art, detailed animation, and an elegant original score. Through the game light puzzles, platforming sequences, and optional skill-based challenges will reveal themselves as more of Gris’s world becomes accessible.

Infinifactory
A sandbox puzzle game by Zachtronics, the creators of SpaceChem and Infiniminer. Build factories that assemble products for your alien overlords, and try not to die in the process.

My library is mostly Sierra and LucasArts adventures. Also a ton of D&D titles I haven't touched.

Star Wars: Galactic Battlegrounds is an all-time favorite.

For the Sierra titles, I'd highly recommend the first Gabriel Knight.

Swat 4 Gold

Tactical FPS where you command a SWAT team in some really atmospheric missions. The gold standard for games of the sort. Ready or Not is a modern game that takes a lot of influence from it.

I just picked up The Last Stand: Aftermath, and have been really enjoying playing that game.

A few of my absolute favorites

• Battletech

• Witcher 3

• Parkitect

It's a bit rough around the edges, but you (or someone else) might enjoy Genesis: Alpha One

You fly a space ship (well, mine usually look more like stations that can also move), across different life-infested solar systems. The main gimmick is that you build the station yourself out of different modules.

So when your scientists come back from planet surfaces, with some spores on their suits, you might find pockets of ewww hiding in the vents of the station you made yourself. You have/unlock multiple times ways to make sure that the infestation stays relatively isolated to, say, the landing bay. But even with those, you'll find yourself doing a lot of first-person vent-crawling to figure out where that disgusting crab-thing just came from.

Plus, it's a rogue-lite with some permanently unlockable progression. There are multiple player factions you can unlock and there's a NG+ mode, but I found myself not replaying it too much (even though my one played campaign was quite fun). Still, I sunk a good 16-20 hours into it, I think.

Spirit Farer & Machinarium are must haves

SWAT 4 is still an excellent tactical shooter the likes of which we don't see anymore, short of Ready or Not, or Doorkickers, if you count that.