Hey. So I tried using a game I downloaded (my own) on downloaded quest, but it didn't work.
Alright, so I extracted the files. But, now I have the "wrong version" and "something something expression" error.

What do I do?

I usually download games from inside the interpreter itself.

That aside, have you tried putting the game into the relevant folder without unzipping it?

if you download a game from the site, it's a 'xxx.quest' file (which is used by the server to enable the game to be playable online), which has to be unzipped, to access the actual 'xxx.aslx' files for the downloaded quest (quest.exe) software on your computer to play the game.

If you're getting a version error... if it's related to the quest engine itself (quest.exe), then you can try checking if your quest (quest.exe) version matches up with your game file's code's specified version (as these do have to match up):

open/start up your 'quest.exe', and on the 'play/create' screen that comes up, click on the 'help' in the menu bar at the top, and choose the 'about', as this will tell you the version of quest (your 'quest.exe') that you downloaded/are using:

only the 2 leftmost digits matter for the version 3 digit number, and the for the 3rd leftmost digit, it's always a '0', for using my own quest download as an example:

help -> about:

Quest 5.6 ---> 560
Build 5.6.5514.32136 ----> 560

versions:
560
550
540
530
520

your version should be '560', as this is the most recent.

next, is to check your game file's code ('xxx.aslx'), just right click on the file itself on your computer (remember if you downloaded it from online, you've got to unzip it first, so that you have access to the 'xxx.aslx' files), and choose to open it, with a text editor software, such as: notepad, wordpad, notepad++, Apple: texteditor, etc

this will show you, your entire/full game code, at the top should be this line:

<asl version="XXX">

those 'XXX" should be a 3 digit number (the version the code is specifying), ie:

560
550
540
530
520
....

if this 3 digit number doesn't match up with the 'quest.exe' version's 3 digit number, than change the code line so that it does, and then save the game file, to save this change you've made, for example:

<asl version="560">

also, note that if you're playing an older game, who's version is 540 or lower, you may be getting errors due to it's coding syntax being the old syntax for List/Dictionary Attributes, which would also need to be changed to match up with the new code syntax for List/Dictionary Attributes, as well as changing the, asl version="XXX", top code line, to match up with your quest engine (quest.exe) version.

if you've had another error, as well as the version error, could you please post exactly what the error is/says, as this will help us with helping you.

if you need help with anything, let us know

"if you download a game from the site, it's a 'xxx.quest' file (which is used by the server to enable the game to be playable online), which has to be unzipped, to access the actual 'xxx.aslx' files for the downloaded quest (quest.exe) software on your computer to play the game."

Ok I've just gone through the process and nothing needed unzipping, the interpreter also immediately opened and launched the game when double clicking the .quest file.

So the OP is doing something wrong...