Styx: Master of Shadows is a really great game and one of my favorite stealth games ever. Don't get me wrong, it's not perfect, but it entertained me really well for 40 hours and did so for a price of 22€. Even if I had payed the full 30€, I would not regret it. Let me tell you why.
There aren't many stealth games around these days and I really miss them. Styx reminded me of how fun they used to be. The gameplay mechanics work really well in this game and there are some that I haven't seen in any other stealth game, such as cloning yourself and booby trapping your clone in a chest or just use it as a distraction for guards. You can even become invisible for short time spans. These things cost you amber which is basically something like mana. You can replenish it with vials you can find during the missions or pickpocket from some of the guards. But those are rare, so don't worry, you can't just walk around the whole level invisibly.
The skill system is also a good thing. It motivated me to get all the insignias and do all the side objectives in the missions, since you get bonus skill points for doing so. With them you can unlock helpful skills such as aerial kills or the aforementioned booby trapping of your clone. You can go for stealthy skills if you like to sneak through the missions or, if you're more into clearing out whole areas, you can invest in more aggressive skills. Every type of player should be able to find some skills they think are cool.
There are also different types of enemies, such as your ordinary guard, crossbowmen, knights, which have plate armor and can only be killed through poisoning or dropping chandeliers on their head, and some more that I won't spoil now. Every enemy has its weak spots and is in his way fun to kill or sneak around.
What I think is really outstanding in Styx is the environment. The level design is just awesome. There are many routes to your destination and you almost always have a choice of how to get there. In synergy with the mostly good graphics (at least good enough for me) and the great lighting effects it often led to me just stopping and looking at the beautiful environments. It's just eye candy to sneak around in the shadows avoiding the bright sun rays falling in a room through a window or climbing a vertical wall in the sunset.
Sadly the fun exploring the levels ends with the exact half of the game. After that you will be back tracked through many levels you have already seen. In most cases this isn't that bad, because there are other guards on other positions with other routes and the levels are still awesome with all the alternative routes. But I have to say that there were one or two areas that just didn't work properly backwards, which was sometimes a little annoying. Nevertheless the back tracking wasn't so bad, although I gladly would have payed 5 or 10 more bucks to just see some more of this really great level design.
The story line was okay for me. It had its suprises and pulled me through the missions and that's all I was expecting from it. The plot is told through voice acting and comic like cutscenes with mostly static pictures of which some were reused a little too often, but that's perfectly fine thinking of the price for the title. The voice acting was good and I personally liked the fact that although the story is set in a fantasy world, the characters swear a lot and talk more like you would expect from real world rogues. That added a special feeling to it and I liked it.
As you can see I have played for 40 hours to get every insignia and every objective. Insignias are badges you get after missions for each of the following things: Staying hidden, not killing anyone, finishing the mission in a given time and collecting all 10 coins in each area of the mission (each mission has 4 areas). In the first run of each mission I killed a lot of guards, stayed hidden, gathered all the coins and did every side objective. The second run was always a speed run without killing any guards and for the fun of it also staying hidden, ignoring everything else. I would estimate that if you just play through the missions doing the side objectives and aren't perfectionistic about being seen or not, you could play through this game in 15 to 20 hours. But where's the fun in that? ;)
Overall I loved this game and though it has its flaws the whole experience is just great, because every mechanic and every element come together to form a really fun time of stealth gameplay. And since it's worth even the full 30€ in my opinion, I recommend this game to every gamer who enjoys stealth games.