Firstly, let's get the marketing side of my review out of the way. Essentially you're paying £15 for four top class, extremely enjoyable games. Truthfully, I could leave the review here as that should be enough for anybody, but let's delve deeper......
You play the role of Agent 47, in the employ of a shadow company of Assassins. The capital letter is important, as you're not merely a sniper on the Grassy Knoll, no indeed. You are a hand-picked, trained since childhood, genetically modified Assassin. Oh yes. The games focus on giving you a variety of hard-to-get-to targets with a variety of interesting ways to bump them off. Will you resort to sniping them from a distance, for example, or will you incapacitate key personnel and assume their identity in order to infiltrate and get up close and personal? Perhaps you'll abandon or stash all your weapons for a stealth entry, or load up on firepower to batter your way through? In the case of Blood Money especially, maybe you'll arrange for a fictional gun shot to in fact be a real one, or for a chandelier to drop on the head of an unsuspecting target?
See people, it really is this dynamic. You actually find yourself thinking like a Hitman - "well if I stash my weapons in there, then I'll be clear from the search at the entrance and then I can pick them up once inside, then I take this guy out while he's away from the guards, assume his identity and get close enough to be able to......." and so on. The ambience and music of the game is engaging and at best enthralling, and the whole deal basically radiates atmosphere.
Things aren't all rosy; for example the AI can be noticeably thick, and seem to like forming an orderly queue for your bullets in firefights. There are the occasional stability issues also, but nothing that will seriously compromise things. Savegame-wise.....well I'm afraid Quicksavers will be disappointed. On the decent difficulty levels your saves are limited, and you'll need to be pretty good to come through some levels without using them all.
But faults aside, you'd be daft not to invest in this. Graphics, though dated now, are still impressive and level design is intelligent and realistic. Gameplay is enjoyable, repeatable with variations, and challanging when it needs to be. You get to be a Professional Assassin, or as near as; How can you lose?