Spherical Nightmares is a Half-Life 2: Episode Two single-player modification. The story takes place in the Half-Life universe and you take the role as Gordon Freeman. Your journey begins in an unknown location.
Replace the original gameinfo.txt in the mod folder with this one. This can be used to fix any HL2 EP2 mod, but then you'd better backup the old file to replace the game title, game type and developer credits/URL with the corresponding info for the mod.