QWEEDDYZ: Topic starter, do not listen them all. Better way - by both Steam and GOG versions.
Until that you must redownload and reinstall offline version of Quake 2 GOG and laucnh it from GOG launcher. Dont forget to visit support page for 2 archives with fixed dll for expansion (GOG missed them).
after first launch, make sure you set up a proper settings.
hudfreegamer saying nonsense. And some local* real old-fags do not correct him. There is no problems with Quake 2, its a problems with current widescreen monitors. 1920x1080 is a less than old normal full-screen 1600x1200. Pay atention on numbers. Set proper settings, set "Keep aspect ratio" in video driver.
If you have 1360x768 - set a 1024x768 resolution. FullHD support only 1024p maximum.
If you still have problem and do not buy yet Steam version - google it mdf\mds quake image files. GOG version never be updated, just 2 separate dll fix - still wrong build that work only from lamo-created broken old GOG launcher.
I'm trying plating on steam, with the same issue. Can you help me with that? I tried KMQuake2, dind't work. Computers are not my forte.