There is no level system, instead you find upgrade canisters a la Deus Ex and upgrade your suits or your weapons, the weapons all have special abilities, overall it's much the same effect as a leveling system, albeit more primitive.
There's no jumping except in zero grav where you get to walk on the walls, which is pretty cool. Otherwise you get the same feeling of wishing you could do more with the environment as in the witcher.
There is no quicksave, but save stations, and a ATMs where you buy upgrades a la System Shock. The baddies are like something out of a Warhammer Chaos army.
If you have seen the movie Event Horizon, it captures the mood pretty well, so far not that much character interaction.