Sequels, love them or hate them, are usually a sign of a successful game. The original F.E.A.R. single player game's ending left you dangling, and was obviously written with a sequel in mind. After the game's original publisher Vivendi bought rights to the F.E.A.R., but then went into serious financial problems, the franchise was left in limbo; Monolith Productions were dropped in favor of TimeGate Studios, who jumped right in and made an expansion, F.E.A.R. Extraction Point. It brought the story of Point Man, the original protagonist, to another inconclusive conclusion.

Reflex Time: like bullet time, but more... reflexive... or something
Now it's time to milk the old cow again, and Timegate is back with Perseus Mandate. The stand-alone expansion introduces a new player character, the faceless, voiceless and nameless Sergeant, who mysteriously has Point Man's formerly unique hyper-sensitive reflexes (read: bullet time). The story parallels the original, with the Sergeant's elite First Encounter Assault Recon squad investigating violence and paranormal activity at Armacham Technology Corporation.
You again battle wave after wave, room after room of cloned Replica soldiers, Armacham's security guards and a new crew of deadly Nightcrawler mercenary forces. The hapless Delta Force troops sent to support your F.E.A.R.less efforts keep getting into trouble, just like they did in the original. The main villains are the same, your commanding officer is the same, and the plot's pretty much still trying to ride the wave of the original game.