This game holds a special place in my heart. It may not be the best Splinter Cell in terms of gameplay and it has for sure many technical flaws and some questionable game design elements, due to the release of the game being rushed, but I love it.
And first of all I really loved the double agent concept and the different main choices having impactful consequences on some of the characters and on the story, that brought a great extra layer of tension to the traditional, great and unique Splinter Cell gameplay. I honestly rarely felt so much tension in a game and it's unique to Double Agent in the series, and even in the entire stealth genre. I think that's what made me love this game so much. Besides I consider its soundtrack and story as the best ones in the entire series, and the Shanghai mission is part of my top 5 favorite missions of the whole franchise.
And even if this game lacks polish and was released too early, it was still innovative gameplay-wise and introduced some new interesting features and gadgets like the ability to swim, takedowns from a corner, the inverted rappel through the winch, the glass cutter, the ultrasonic emitter, the safe-cracking minigame, the ability to hide under a truck or a desk,... If the devs had the opportunity to properly implement these mechanics and features, I'm sure this would have been the ultimate Splinter Cell game !
I've always dreamed of Ubisoft finally patching this game and fixing it once and for all because this game gets so much ignorance, rejection and bad reviews because of its poor optimization. Sadly I know they'll never do this, so hopefully we can have it on GOG with the patches, the fixes and the widescreen resolutions included.