Skulltag - Classic Doom online, Modern, beautiful, and fun: Skulltag is by far the best way to play Doom online. Supports Doom 1 and 2, Heretic, Hexen, and Strife. Skulltag adds fresh features to these titles' classic gameplay. Skulltag brings the classic Doom into the 21st century; maintaining the essence of what has made Doom great for so many years, and at the same time adding new features to modernize it, and create a fresh, fun new experience.