Or is there at least a way to have it not stretch to fill the whole monitor? I'm thrilled to play the game again, but having everything be distorted is a bit distracting.

OK, figured it out. If you have an NVidia card, go into the NVidia control panel, and under 'Adjust desktop size and position', set the scaling mode to 'Aspect ratio' (should be the default), and then (this is the important bit) in the "Perform scaling on:" drop down just below that, make sure it's set to GPU rather than display. This way when you launch the game, it should give you black bars on either side so that the actual game (including all the live action videos where you'd really notice the difference) is in a 4:3 aspect ratio. If you have the drop down set to 'display', the whole thing will stretch to fill your monitor, and if you're anything like me, annoy you horribly.

It's called "Borderless Gaming". I've tested it today and found out ST:SA for some reason won't let me ALT+TAB out of the game :-/

They may have disabled it via the shortcut or via ACT. You could try installing Microsoft ACT (free download from MS) and fiddling around with it, but be careful with it as you can really F things up if you're not careful with it. :)

Hey, this problem has been solved using DxWnd https://sourceforge.net/p/dxwnd/discussion/general/thread/6bd6e36b/

It looks great in the proper ratio :D

Cheers :)