PrBoom+ is a Doom source port developed from the original PrBoom project by Andrey Budko (Андрей Будько).
The target of the project is to extend the original port with features that are necessary or useful for me personally and to all those interested in my work. It is worth noting that all changes introduced by me in no way break PrBoom's compatibility with the original Doom/Doom2 engines, and it is possible to be confident this will never happen in the future since compatibility is as important a merit of PrBoom as it is to me.
Doom-plus is a patched version of the original DOS exe for Doom2 (version 1.9) with increased limits to reduce the risk of crashes, premature program exits and certain visual problems. This is done without loss of compatibility - in other respects, Doom-plus behaves exactly like the original DOS exe. Dehacked patches can be applied as normal, for instance, and any demo that plays back correctly with Doom2.exe will also play back with Doom-plus.