anchor.diff:  CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 208200" "InstallLocation"
   IF NOT "%REG%" == "" (
   	REM # check if DOOM.WAD can be found there
  +	REM # TODO: this WAD is broken and censored and we should patch it automatically
   	IF EXIST "%REG%\base\wads\DOOM.WAD" SET "IWAD_PATH=%REG%\base\wads\DOOM.WAD" & GOTO :iwad_check
   )
   REM # is GOG : DOOM 3 BFG Edition installed?
   CALL :reg "HKLM\SOFTWARE\GOG.com\Games\1135892318" "Path"
   IF NOT "%REG%" == "" (
   	REM # check if DOOM.WAD can be found there
  +	REM # TODO: this WAD is broken and censored and we should patch it automatically
   	IF EXIST "%REG%\base\wads\DOOM.WAD" SET "IWAD_PATH=%REG%\base\wads\DOOM.WAD" & GOTO :iwad_check
   )
  +GOTO :iwad_check
   
   :iwad_doom2
   REM --------------------------------------------------------------------------------------------------------------------
  -REM # are we looking for "DOOM II"?
  -REM # (if not, skip ahead to TNT)
  -IF /I NOT "%IWAD%" == "DOOM2.WAD" GOTO :iwad_tnt
  -
   REM # is Steam : DOOM II installed?
   CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2300" "InstallLocation"
   IF NOT "%REG%" == "" (
  
positive.code: 
  REM # this is where the IWAD is assumed to be
  SET "IWAD_PATH=%IWADS%\%IWAD%"
  REM # the IWAD exists as-is and requires no special provisions,
  REM # skip ahead; no edge-cases to handle
  IF EXIST "%IWAD_PATH%" GOTO :iwad_found
  
  REM # IWAD is missing,
  REM # now search GOG / Steam for the IWAD:
  
  :iwad_doomu
  REM --------------------------------------------------------------------------------------------------------------------
  REM # are we looking for "The Ultimate DOOM"?
  REM # (if not, skip ahead to DOOM II)
  IF /I NOT "%IWAD%" == "DOOM.WAD" GOTO :iwad_doom2
  
  REM # is Steam : The Ultimate DOOM installed?
  CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2280" "InstallLocation"
  IF NOT "%REG%" == "" (
  
negative.code: 	REM # check if TNT.WAD can be found there
  	IF EXIST "%REG%\TNT\TNT.WAD" SET "IWAD_PATH=%REG%\TNT\TNT.WAD" & GOTO :iwad_check
  )
  GOTO :iwad_check
  
  :iwad_plutonia
  REM --------------------------------------------------------------------------------------------------------------------
  REM # is Steam : Final DOOM installed?
  CALL :reg "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Steam App 2290" "InstallLocation"
  IF NOT "%REG%" == "" (
  