Styx is, well, pretty cheap. The graphics aren't much and the music really isn't much. I encountered some bug critters last night that are blind but have great hearing so I tried to get a few to attack the guards a floor above them. Nope. Seems they only eat Styx, not humans. The gameplay is fun, though, and the voice acting is well done. It isn't about the knock the old Thief games off the stealth throne but it's good enough.
It also has ridiculously low achievement rates. Less than half of all "players" even finish the tutorial mission. I guess with those cheap prices, a lot of people buy without even looking at what the game actually is. They get it, install it, start it, and quit very quickly. (I'm pretty sure you actually have to run the game once to count as a player - just owning it isn't enough.) If you're looking for a game where you can get rare, glowing achievements then this one can get them to you pretty quickly.