Fun fact about stealth mechanic rewards in the original: they don't vanish if you did the offensive approach! You could get the most xp by first killing everyone and then run around through tunnels and obstacles to get the other half of the xp
I remember the escape from his brothers apartment in hells kitchen especially fondly because of that. First you slaughter everyone so your bro is safe for offensive reward, then you run through the level for the discovery rewards such as enabling the turret which shots the now non-existing enemies (the brother dies if you don't block him by standing in the way so risky to do earlier) and finally escape through the window. 3 routes and you get all the xp :)