I would choose Splinter Cell because the mark & execute system is probably the most controversial change to the Splinter Cell series. You can tag or "mark" enemies, putting a big arrow over their heads and then executing them with the press of a button. So long as the mark is red, you are guaranteed a kill. As it's described, this would seem like a "win" button that would make Splinter Cell too easy. Far from it. You have to work to earn the right to execute. Use it once and you must perform another stealth takedown to activate the execution option again. More importantly, executing does not equal "stealthily execute." If you aren't careful, you can easily expose yourself to enemies when you enter execution mode. There are often more enemies than you could ever mark, so it's not as if you run through tagging and killing with ease.