When you buy the modern enhanced version of , you typically get access to the original 1994 DOS files as well:
: GOG provides a DRM-free version that includes the original DOS files, often pre-configured to run on modern Windows via DOSBox. Download Doom 2 PC Game 1994
Since is still actively sold and supported by Bethesda, it is not legally considered "abandonware". While you can find files on archival sites, the safest and most reliable way to get the original 1994 experience on a modern PC is to purchase it through an official digital storefront. Where to Legally Download When you buy the modern enhanced version of