The remainder of Perseus Mandate may not match the underground level, but it's still a significant improvement over the first half. Levels have more interesting settings, and there's an increase in paranormal activity (for example, Paxton Fel makes most of his appearances in the latter part of the game). While you're still fighting primarily human opponents, there's more variety, mostly because of increased contact with the Nightcrawlers. Some of the more dangerous Nightcrawlers are pretty much ninjas on crack. They can practically climb walls, and effortlessly leap into the rafters, making for tricky targets. They seem to possess the same heightened reflexes you do, so even when you have that ability activated, they can still suddenly dodge out of your line of fire, leaving you blasting away at thin air. And they take a shipload of damage to take down. Fights with the Nightcrawlers are essentially boss battles, providing the most chaotic, challenging, and enjoyable combat in the game.

The game introduces a trio of new weapons, but only one will have much of an impact. Ammo for the lightning gun and grenade launcher are so rare that you're not likely to use them for more than a couple of fights before having to abandon them - they're really just a tease. But the third weapon, an advanced rifle with a neat infrared scope, will likely become your bread and butter gun, at least against non-armored opponents. Essentially adding only one useful gun is indicative of the expansion's general lack of new content and features.

Perseus Mandate is certainly not without merit, but it doesn't stand out enough to give it a whole-hearted recommendation. If you dig the F.E.A.R. universe and haven't quite gotten your fill of its particular style of clone-killing, office-trashing gameplay, then by all means, give it a go, just bear in mind that you're not likely to enjoy it as much as the original. But if you didn't particularly enjoy F.E.A.R., or are just looking for the best shooter out there, you're better of skipping it.