ZDaemon
 

Does anyone know this?

It's a online Variante of classic DOOM! You can play in a network or against many people all around the world!
The program is based on wad files. The original DOOM Shareware File is put in, but most servers in it request the DOOM 2 wad file, so it's always nice if you own DOOM II, so you have the most fun ;)

I know of it, Skulltag is superior to it, however. Also, the term you are looking for is 'source port', not 'game'.

oh yes... corrected it