A seven-mission campaign, Perseus Mandate isn't exactly large, but it doesn't outstay its welcome and there are three bonus missions unlocked when you complete it. FEAR's horror/action/slo-mo domain remains modern gaming's equivalent to the missing-in-action Max Payne. Fans won't be disappointed. But despite being standalone, the pack is less easy to recommend to newcomers. The game does a spectacularly bad job of introducing you to its fiction, assuming that everyone knows about the ATV Corporation and why you may be shooting them, and who that spooky girl and bloodstained geezer are. While you don't have to suffer extended cutscenes, the narrative is simply confusing. Also, outside of the vivid hallucinations, the environments are boxy and continue the concrete-with-everything scheme. There's also a little too much Halo-esque repetition of scenery.
But much like Halo, if you're looking at the environments that closely, you're missing the point. FEAR is about the action - either pillars and flesh exploding as a round collides with them, or the sudden, disturbing stab of light and sound in the horror sequences. And in those terms, Perseus Mandate does nothing to disgrace its lineage.