Or SD card. Basically, I'm looking for some chill little indie games to play at work that don't require actual installation on the work PC. This means save games are stored on the flash drive as well. Any ideas? Games like Defender's Quest would be good, though I don't think that one works. Mouse/Keyboard needed as well.

Not an expert, but...wouldn't that require you to have some OS installed on that SD card?
I mean - the games need to be installed first, and - to my limited understanding on these issues - once they are installed, they have "dependencies", "fix points", "anchor-files" within the system under which they are installed.

So, an OS needs to be installed on that SD card, right? An OS under which the GOG games can be installed and run.
Oh, and that "encapsulated" SD card OS would still need access to your work PC's monitor and KB/mouse.

I don't see that as possible.
But again: not an expert.

Games that run on DOSbox should be small enough in most cases, but it really depends on the size of your flash drive.

It should work fine if he installer the game on his PC and moves the install folder to the Flash drive. Works with external HD. This is GOG we talking about, not steam. haha

Edit: OP police stories is small and fun game.

Yeah most games install in a way that they integrate more with the OS (and put save/config files on the C: drive). But they don't need to be installed ON the OS drive. 95% of my games are installed on secondary drives.

However, there are a few games here and there that are DRM-free and can run entirely from a secondary drive, with the save and config files saved in the installation folder. That's kind of what I'm hoping to find. That way there's no need to do an installation to the specific PC I'm playing the game on.

From GOG, I'm pretty sure that Spelunky and Jazz Jackrabbit 2 are portable and keep their saved games somewhere in the game's directory and not in your user folders.

You can also put a bunch of OpenBOR games on a USB stick, like Golden Axe Returns, Golden Axe Legend and many others.

For portable games, PCGamingWiki is probably your best guide. When you see "path-to-game" for both the Config & Save file location, then the game is probably portable. Simply copy the game folder to the USB stick, run the game .exe from the game folder and those "path-to-game" games should save to the stick). Anything that saves to %DOCUMENTS%, %APPDATA%, etc, isn't going to be portable.

Portable DOSBox Games:-

GOG's DOSBox games are usually portable, however simply copying the folder from drive C:\ to the USB stick will leave the shortcut link in the folder with the wrong drive letter / path. To fix this, edit the shortcut in the game folder and it should look something like:-

"C:\GOG Games\NAMEOFGAME\DOSBOX\DOSBox.exe" -conf "../dosbox_NAMEOFGAME1.conf" -conf "../dosbox_NAMEOFGAME1_single.conf" -noconsole -c "exit"

where "NAMEOFGAME" is the game name. Change the first part C:\GOG Games\NAMEOFGAME\DOSBOX\DOSBox.exe to whatever the USB stick path is, eg, if you copied it to D:\DOS Games\ then change it to "D:\DOS Games\NAMEOFGAME\DOSBOX\DOSBox.exe" and it should work.

Portable ScummVM Games:-

GOG's ScummVM games are usually portable, however simply copying the folder from drive C:\ to the USB stick will leave the shortcut link in the folder with the wrong drive letter / path. To fix this, edit the shortcut in the game folder and it should look something like:-

"C:\GOG Games\NAMEOFGAME\scummvm\scummvm.exe" -c "..\NAMEOFGAME.ini" TITLE

where "NAMEOFGAME" is the game name. Change the first part C:\GOG Games\NAMEOFGAME\scummvm\scummvm.exe to whatever the USB stick path is, eg, if you copied it to D:\ScummVM\ then change it to "D:\ScummVM\NAMEOFGAME\scummvm\scummvm.exe"

(edit: apologies for the borked formatting but there's no way of stopping GOG's forum from auto-justifying it).

The DROD games work fine.

Sort of. Only the first two DROD games are portable (King Dugan's Dungeon & Journey to Rooted Hold). DROD 3-5 save their games to %PROGRAMDATA%/Caravel.

Little Inferno?
EDIT: Oh. You wanted saves to be independent as well. :S
That's pretty rare - most save to specific HDD locations.

I'm guessing said "work PC" is Windows based (and not MacOS or Linux) ?.

Celeste was portable, saves games and all, don't know if still is.
I seem to recall Brigador up Armored and Shantae Pirate Curse are portable as well.

On PortableApps you can get some nice simple puzzle games, I particulary like Sudoku, 2048 and PuzzleCollection. You can download the zip and extract the portable folder.

For games that don't require actual installation but can use the "Documents" folder to save the game, don't know if is fine to you but here are some:

Into the Breach
SteamWorld Heist
Bastion
Battle Brothers
WonderBoy and Dragons Trap

Most Unity engine games write to the %appdata/local% folder so they are out of the question.

Edit: Just remembered, Hearthlands is portable as well, not sure if it flips any registry key though.
Note that some portable games still have some dependencies that need to be installed on the machine, like VC Redistributables. Without them the computer will spit a "random" DLL error.

There's plenty of games that fit that requirement, I'd say on GOG alone it's thousands. If you avoid open world games that require constant fast loading, the only important factor is the size.

I usually have part of my ScummVM collection with me, when I am on a business trip, also some non supported p&c adventures.
But there are also plents of 2D platformers, some have already be named, also games like Cat Quest work without problems.


edit: But be aware, that most games will write savegames into your documents directors or "%localappdata% or %appdata%

Dude said "chill games" man not stress inducing ones hah ! :P

Recettear is pretty chill mostly and 100% portable with saves in main game directory. Unfortunately it's not on GOG anymore... however Steam version is DRM-free after patching (doesn't need client or anything)...