Warning: There are (minor) spoilers about Deus Ex: Human Revolution in this review, so proceed with caution if you've yet to finish the main game.
The first piece of DLC for Deus Ex: Human Revolution wipes the slate clean. It's an opportunity for players who were disciplined in a certain style of play to acquaint themselves with another. For those who passed through the game as a shadow, it's a chance to crack out the guns and start causing a ruckus. For those that killed everything in sight, it's a chance to take it down a notch and try out the more elegant stealth side of the game. Or not. Whatever. You could choose to play the DLC in exactly the same way as you did before. Nobody's going to make you do anything you don't want to. Such is the beauty of Deus Ex.
The Missing Link is named well, taking place in that hazy gap between Hengsha and Singapore. Jensen wakes from stasis and finds himself sat trapped in an EMP chair, which renders all of his augmentations little more than dead metal. His captors - Belltower agents - smack him around for a bit before bombarding him with questions. Ever the tough guy, Jensen keeps shtum. The interrogation scene lasts little more than three questions, and could have been drawn out much longer. That said, your choices here do affect what equipment you'll recover later on in the game. Choose an aggressive response, for example, and you'll be rewarded with guns.
After being left unsupervised, the shackles on his wrists and feet are released, and Jensen is able to make his escape. Through a ventilation shaft, obviously. The Missing Link plays out like any other mission after this point. It's longer, though - weighing in at four or five hours, less if you're good - and self-contained in terms of plot. Light is shed on some aspects of the main story, particularly Megan Reed's research, but the DLC has its own plot and themes.
In terms of what you're actually doing, the formula is familiar: you'll move from objective to objective, taking out (or strategically ignoring) guards along the way. Some new weapons or augmentations might have mixed things up in this respect, but in their absence the game plays much as you'd expect.
The environments are new, of course. The boat is more claustrophobic than previous areas, and benefits from a tweaked aesthetic and improved lighting. The area you'll prowl about is littered with short cuts and alternative routes. The level design promotes a stealthy approach, which is reinforced by the voice - an unknown accomplice acting as your handler - jabbering on down the comms system; they'd much prefer you to be quiet.
It isn't long before you'll recover your gear, at which point you'll also be given seven Praxis kits. How you choose to spend these will determine how you're going to play the remainder of the DLC. I chose to keep hold of them until I needed a specific skill. Arriving at a level 2 security terminal, for example, prompted me to invest some points in hacking. Later, after not wanting to kick up a fuss in an area teeming with guards, I bought the stealth cloak. If you ignore this flexible method and blow them all at once, however, there's still an opportunity to earn more kits by levelling up in the usual way.
Anybody that has finished Human Revolution will have tinkered with most augmentations already, so restoring Jensen to factory settings doesn't actually offer the player much new from a gameplay perspective, which was one of the supposed intentions of the DLC. Sure, it's an opportunity to try out a new approach, but it's likely that many people will stick to the same tactics - to the same character - they played the first time around. By the end of the expansion you'll have invested 10, maybe 11, Praxis kits on Jensen, all of which are gone by the time you arrive in Singapore. Quite why none of these augmentations show up after the DLC is never explained. It's a minor issue, ultimately, but continuity errors like this are frustrating in an otherwise cohesive game world.
In my preview last month, I expressed concerns about the linearity of The Missing Link, and while there are no hubs, the game does open up slightly about half-way through. Over the course of the narrative you'll be introduced to a merchant, an Irish chap with an augmentation that has left the outline of a big circular disc on his face. At this point things open up somewhat, and you're no longer forced down a set path. There are two side quests in total, one taking the form of a fleeting detour earlier on in the game, and another from this merchant. It's at this point that you can return to areas of the boat you've already visited. Exploration becomes more important, and things become more free-form in nature as a result.
While Human Revolution was universally panned for its boss battles - which snatched choice out of the hand of the player, replacing it with one-on-one gun-slinging matches against an opponent with a health bar much longer than yours - The Missing Link manages to avoid such pitfalls. The one and only boss battle, which rounds off the DLC, is rife with options and strategy, offering a large playing area and multiple opponents. It's a fitting finale, and something similar that would have slotted well into the main game.
While Jensen appears to have forgotten the entirety of what happened on the boat by the time he gets off in Singapore (a plothole similar to the missing augs), it seems like the events that unfold in The Missing Link - or more importantly, the people you'll meet along the way - could play an important role in the inevitable sequel. I'll say little more on the subject other than that, but despite not having much of an impact on the remainder of the main game, it raises some interesting questions.
For 1200 MS points (£8.99 on PS3 and PC), you'll also get 10 new achievements/trophies, which could help persuade somebody into parting with their coin. It's a steep price though, considering the five hours of content you get. It would be easier to recommend The Missing Link if it didn't feel so disjointed. Nothing that happens, both in terms of plot or augmentations, has any bearing on what follows. Those that have finished Human Revolution will simply be grateful for more Deus Ex, but taken out of the context of the main game, with its hub worlds, huge cast of characters and grandiose conspiracy, it doesn't offer enough to be considered an essential add-on.