In an Australian edition of GI, i remember them saying that their next game was to be a mixture of Deus Ex, Ultima Underworld and (i think) Arx Fatalis.
Never played any of these games so i'm not sure what to expect.
a quasi-linear game with open mission structure where you can step off the critical path to cook a rat over a barrel-fire, or find more information about the current situation, but not enough that you can just [censored] off and ignore the plot(s) forever, like you can in a Bethesda game. possibly hub-based, with a wide variety of sidequests, some or most of which will likely have consequences down the line.
probably mostly first-person, if not entirely.