Having played all Splinter Cell games, I find Double Agent the most intriguing, but definitely not the most challenging in terms of difficulty. (I still think Pandora Tomorrow is the most difficult to date.)
There are some very challenging moments, but those shouldn't be a problem, because you can save at any time. This is really handy if you're playing in Elite mode. The 2 most challenging levels are (to me) Kinshasa, in which you start off with no gear at all, not even night vision and you have to deal with very smart guards. Then there's New York, in which you have to deal with guards equipped with night vision. Unlike the guards with thermal vision (Chaos Theory > Bathhouse level > shower room) there's a simple way to take out these, once you've figured it out.
I finished the 9 levels (+ 2 bonus maps) in a day and a half, so I was quite disappointed that it was all over so soon. (That's what happens when you play day and night, lol.) One of those bonus maps is definitely the weirdest level in Splinter Cell history!
The replay value is VERY high, since you can change the story as you choose for either JBA (the terrorist group Sam has infiltrated) or NSA (the government agency that Sam works for). After every completed mission, you'll find out which side is suspicious of you and who is confident of you. It's up to you to keep both sides satisfied. For example: you can choose to disregard opportunity objectives for the JBA in order to keep the NSA satisfied.
The enemies have gotten smarter. Guards patrolling in dark areas almost always have a flashlight. If they don't, then they probably carry a torch. They have also invested a serious amount of money in security cameras, lasers of different kinds and non-lethal ammunition. From the moment your visibility meter lights up even a little, they'll check out what they saw. (And sometimes they notice your presence when you're completely covered in shadows.) Their hearing has gotten a lot better too, so you should always be sneaking, if you didn't do that already. You'd better not take your gun out if an enemy is standing a few yards further, because they'll hear it. These enemies are very sophisticated and smart and that's what makes them so cool. The interrogations are always worth listening at, not always to collect information, but also for fun. The real challenge will be on the day that Ubisoft will create enemies with random patrolling routes.
A new, and I must say a very satisfying difficulty is Elite. You unlock this difficulty by beating the game. You have no weapons, no gadgets. Only the OCP to jam cameras/lights, a knife and the ability to whistle. You have to rely on your map and your sneaking skills. It's so much fun, but might get the unexperienced 'splinter cells' extremely frustrated. Be sure to keep your eyes open for flash bangs and smoke grenades in dark corners, because if they're there, you bet you need them later on. The whole game can easily be played in Elite mode, when you decide to game on a lazy Sunday afternoon. You have to take your time to do this, thinking about the different routes you can take, memorizing patrol routes of guards, etc. You'll start to appreciate it more and more every time you play it. Another improvement is that you can't accidentally whistle by pushing the wrong button.
There are also levels in which you have a teammate. You can tell them to wait or follow, which comes in handy if you want to explore the environment and take out the hostiles before they open fire on one of you. (Sam carries an adrenaline syringe, just in case.)
The controls are the same as in Chaos Theory, so it's easy to catch up on that, if you played it. The voices are again very well done and very realistic, maybe even better than in Chaos Theory. Sound and graphics are as good as always. The music alone is worth listening at. If there should be a soundtrack coming out, I'm definitely gonna buy one.
I wouldn't recommend this game to those that haven't played Splinter Cell games before. You always can, of course. It's not that hard to get to know the controls and the people. It's just more fun to play this game after you know what missions Sam has done in the previous games.
I'm going to rate it 10/10, because of the great time I had while playing. I have to say though that 2 levels take place in the same environment, which narrows the adventure down a bit. And also that it can be finished in no time. It's very different from the other Splinter Cell games, but I like this new approach. (I do miss Sam's haircut though :) Aside from that, it's worth every cent and minute of your time.
