Here is the source code of DelphiDoom. You need Delphi (version 6 or greater) to compile it. Also tested with Free Pascal Compiler 2.2.0 but it's not stable.
This download contains the source code, easy launcher and the binary executable of DelphiDoom. Also includes the shareware game data (DOOM1.WAD).
DelphiDoom executable and easy launcher for Win32 operating systems. You will also need a main WAD (IWAD) file.