Kongregate free online game Doom 1 - = DOOM = The first episode of the legendary first person shooter now playable in your browser! . Play. Doom II was not dramatically different from its predecessor. original Doom as normal level enemies, in addition to adding a new weapon, the double-barreled. The original game is divided into three nine-level episodes and distributed via shareware and mail order. The Ultimate Doom, an updated release of the original.