Mini-Review
1) The first mission has you play as a Reich Heavy called Hans, a heavyweight trooper of the Neo-Nazi faction who has been sent to fight on the battleground featured in the nostalgic level of Metro 2033 called "Frontline". Since Hans is practically a walking tank, coated in thick armour and packing some of the most powerful weapons the Moscow Metro has ever seen, his mission is (expectedly) the most action-packed of the three… and that fact, unfortunately, makes it the most disappointing. It is practically a shooting gallery, but one that shoots back. The whole sequence is a spectacle of well-designed chaos; however, it doesn't feel like anything remotely related to the universe of Metro 2033 and it doesn't last that long either. You won't find the amazing atmosphere, stunning story or charismatic characters of Metro: Last Light here.
2) In the second mission, much like in the first one, you are forced to adapt a certain play style – but one vastly different to that of the Reich Heavy. Here you will play as the Red Sniper, sent to assist his comrade in the taking of a Reich-controlled outpost on the surface of the Earth. Armed with an awesome weapon that was cut from the original game, you must make your way stealthily through a great reincarnation of the "Black Station" level from Metro 2033. Although you must not allow your enemies to raise the alarm or it's game over (so you're limited just like in the first mission), the premise of the second mission is in itself a lot more interesting than that of its predecessor. It is also executed in a better way – as it lasts longer, is much more atmospheric and gives the player more freedom.
3) Lastly, the mission entitled "Kshatriya" is the best of the three. Here you take the role of a Polis ranger in training, who has proven himself worthy to venture above ground and return with supplies that can only be recovered from the surface of the Earth. In Kshatriya, the survival horror gameplay elements only partially visible in Metro 2033 and Last Light really shine. The whole mission shows what the life of a "stalker" in the Metro 2033 universe would actually look like. It's a glorious mixture of tense gameplay and semi-open level design that adds up to make something extraordinary. You'll even get to revisit the "Library" level that Artyom had to make his way through in the first game.
In the end, the Faction Pack is a must-have for any fan of the Metro 2033 franchise simply for the Kshatriya mission alone – with a bonus in the form of the Red Sniper mission and the nasty surprise of the Reich Heavy. It doesn't have much to offer in terms of storytelling, but it's a real experiment in the form of gameplay… one that is mostly successful and is worth the small price it costs.