Well, temptation and curiosity got the better of me. I downloaded the ripped version of DM (it's basically the single-player files from the Steam installation). It runs very nicely. I got it because I had to see for myself the issues everyone was complaining about, and the gripes with the 'linear' gameplay.
After playing through the game several times, and seeing 4 endings (similar but with subtle differences), I've come to the conclusion that it is a great game. It is fairly linear, but there are a few moments where you can create a turning point. The locations will be the same no matter what choices you make, but how they fan out may differ. Your choices can make an ally who may aid you in a coming battle, or an enemy that will obstruct your path. So it's not as strictly "linear."
This is the first game in which I was more tempted to be "dark" despite my classic tendency to be "the pure of heart" hero. Basically there are 3 paths: be with the "good" girl, be with the "demon" girl, or be alone. Each path is relatively obvious, though there are some interesting revelations along the way. The 3 paths can also be considered as for the greater good, for the greater evil, or for yourself. Normally I'd be the "I shall do it for the greater Good" sort, but in this game, I was way more emotionally agreeable with completing tasks for myself! Call it sinful, but damn it, it made more sense! The "evil" was purely evil, and had no interest in keeping me around, and the "good" were stuck-up, self-righteous bastards! So screw 'em both!
The gameplay was very enjoyable! As usual I played it in a very stealthy fashion, so making good use of the traps laid out about the environment was truly satisfying! Whether it's cutting rope which releases a swinging slab, breaking a weak support pole, or simply shoving an enemy on a trap-platform to activate a deadly trap, it was all good fun! The rope-bow is a really handy tool, giving you a greater command over the places you can reach. This is one game where paying attention to your environment will reward you handsomely!
Obviously, the bugs are a drawback. Some can seriously deteriorate the gameplay, especially when it stalls and stutters rendering it unplayable! Fortunately that was a rare occurrence, but it should be addressed! The other tedious bug is the HUD corruption. Sometimes (usually during the stuttering) the HUD will just appear corrupted with a lot of magenta overlaying the slots (probably where the transparencies are supposed to be). Luckily, this can be easily alleviated by quicksaving and quickloading. Another slight issue is the lighting. In some areas you enter you'll notice the lighting/shading flickering as you move or look around. One more irritating bug has to do with clipping; sometimes while I'm attacking an enemy and I back him up to a wall, he'll just suddenly fall through the corner of the wall and floor, and I can still hear him for a little while before he suddenly disappears. That's as far as I've noticed in graphical bugs. The A.I. is decent, but I've noticed that sometimes when you press 'use' on an ally to tell him/her to stop, they'll stay in place (as expected) but you'll be unable to click 'use' again yo get them to follow you again. It's very frustrating when a certain NPC is needed later for some dialogue in a cutscene. There are a few other minor bugs here and there, but nothing serious.
Other than all that, the game is very well done, and a big step for Arkane. I think you'll especially appreciate it if you've played Arx Fatalis. You will note the improvements, and really respect Arkane for their development