I'll recommend this game, but only if you can get it on a sale of some sort.
While the game is a little bit glitchy in terms of saving from time to time, most of the time it holds up really well. After validating, I've only had it crash once. Translations aren't perfect, and some of the words are just really hard to pronounce, much less know how to spell off hand. Though, this isn't really obstructive to gameplay, given you can easily figure things out if you think for a few moments.
The game won't tell you all the default keys, you're going to want to check those, as the tutorial isn't going to answer that for you either. The tutorials frankly aren't that beneficial, they'll give you the very basic, but fully employing something is going to take trial and error.
Actual gameplay wise... The game is great really, you're not restricted to just being the heavy armored titan who shambles along mowing down everything he sees. Sure, in the beginning you're going to be more or less locked into the basic strategies of, long range versus close range... But very soon, you'll be able to make yourself capable of stealth, tanking, hacking, and more.
To explain what I mean to those thinking of buying this game:
The game does have a stealth system. It's normally impossible to be stealthy unless you use the cloak implant that you can buy pretty early in. If you hit someone who hasn't detected you, you will get a pretty nicely sized modifier to your hit.
Hacking; is actually a very powerful tool in the game if you can get a few good strategies for it going. You can quite literally make your enemies turn against each other, ignore, and even defend you. You can take a glance through someone's eyes... Or you can flat out cause brain death by hacking a person. However, hacking isn't possible on all enemies in the game.
There's varieties of every type of gun in the game, each with a unique aspect. Just looking at melee, the Distortion Hammer is big, heavy, slow... But it causes massive damage, and it can work great as a shield (yes, you can block using weapons, bigger weapons are better at blocking). There's also the dual blades, which are fast, lethal, but lack the damage per hit and blocking power of the hammer. In short; you can play it light, quiet and quick... Or big, heavy, and monsterous... With any weapon really.
Your "special" stuff doesn't come from killstreaks or anything like that, no, they come from two branches of specials, which are purchasable/earnable. Cyber Implants and Psy Powers. Implants are all purchasable, but psypowers; some are purchasable, others have to be earned.
Cyber Implants have mostly basic effects, improving your aim, hardening your skin, making you invisible to enemies, making you jump higher and run faster...
Whereas Psy Powers... Are much more specialized. Creating tissue paper clones of yourself to shoot at enemies, turning ammo into health, health into energy, killing and teleporting to your target, among others.
Now, the reason why I say that you should buy this game if it's on sale...
Is that while it's well made in terms of creating an atmosphere, being unique, and giving you plenty to play with... The actual stuff you'll be fighting.. Is pretty slim in diversity.
Sentries, Scrabs, Jiang, Carnophage, Looter, Manduco, Synicle, Federal Cop, Special Force, Deus Ex, Interceptor, Kraak, Perigrum Forma, and Patrol.
That is every non-named in the entire game. Which as you can imagine gets pretty repetitive. Different weapons but pretty much the same thing.
You can configure AI, but most of the time, enemies seem to be great at finding, and shooting you even from long distances. Even on the lowest "reinforcement" spawn, you might find yourself swarmed with over a dozen of a single enemy, who automatically path towards you from their spawn point just a few feet away. Yes, that is a problem with the game, respawns of enemies are pretty bad. They'll spawn at set points, ones which can be easily memorized given they're largely just open space most of the time, and you can literally walk to that spot... Wait, and then take newly spawned enemies by surprise, mowing them down with ease.
Not all gamestyles are that rewarding.
If you hack a lot, you'll find you're getting a disproportionate amount of XP to money.
If you sneak a lot (ghosting through missions, which is possible nicely enough), you'll find you're low on everything, given there's not much of a bonus to being unseen at all times aside from getting shot less.
If you raise a machine army of Scrabs and Sentries... Expect them to die. If a non-machine ally gets hit by one by accident (very easy given sentries are machine guns), they will kill your machine.
Ally AI is pretty bad, you'll find yourself getting trapped in corners and in hallways by allies who don't realize you trying to walk through them is a cue to move out of the way... And often times, when they do move, they'll move just to get in your way again, because you found a way past them. They're also totally dumb in terms of vision and sound. If they didn't get shot, and they're not looking at whoever's firing dozens of rounds a minute... No matter how many times you get hit, they will not turn around to help you. Your only hope is to just pray they randomly turn in time to help you. Allies especially are pretty bad when it comes to getting in the way of you defending yourself. They are quite literally the last thing you want when you're using a sniper rifle at long range, as they won't hesitate to step in front of you right when you're aiming, or even shooting, causing you to have to move so they're not blocking you anymore... Or just kill them.
All in all...
The game is a great idea, it's got a great design... But the amount of small things that will make you go, "That's such a simple thing... How could they not get that right? Or at least fix it?" is pretty high in number. The game does make you think though in terms of strategy, using your environment to your advantage, which is definitely it has going for it. But I digress...
Unless you have played it before, or you have cash you're willing to gamble, or it's on sale...
Don't buy it.
If you end up liking this game, chances are... You will LOVE it. But it really depends on who you are and what you look for in a game. It's not your typical FPS, it's not your typical RPG, it's not your typical anything really. It's a mash of several genres, and while I do love it, and recommend it...
I do understand it's not for everyone; the environment/lore might be a turn off for people, or you might find it to enhance the experience. This formula works out for many aspects of the game.... And so like I said;
It's one hell of a game. Whether or not you love it, is on you.