Just finished this up a few days ago. It has some frustrating levels at times and I was about ready to stop playing and move onto the second game in the series but I'm VERY glad that I didn't - read Syphon Filter 2 description to understand why.
The story was interesting, but the gameplay took some getting used to, especially when enemies wore flak jackets. Good lord, I can't even count how many times that I died in the earlier levels because an enemy would dart out from a corner with a flak jacket on and run toward me guns a'blazin! Needless to say, headshots are a must in this game as you progress.
Syphon Filter 2
As I said with Syphon Filter 1, I am so glad that I finished that one before playing this game. It starts out directly after the first game and tosses around the names of the characters from the first game back and forth just like you came right out from playing the first game when starting this one up. There are no flashbacks to help out.
The gameplay has much more variety on the whole. You have shooter missions and sneaking missions placed throughout the game that help to keep it from the feeling repetitive. There are many more cutscenes this time - at least one before each mission.
In terms of story, the sequel makes the first game seem like a mere stepping stone to the events that happen in this one. The plot involves both Lian and Gabe this time equally instead of everything centering around Gabe's progress. Lian is also played quite a bit in this one - much more than she was used in Dark Mirror.
The first stage for this game was a major turnoff though. It takes place on a snowy mountain and the stage can get a bit confusing at times. Also, why in the world do they throw in so many enemies with flak jackets on the first stage? Come on, this is the very beginning of the game!
Overall, I'm really happy with this one and can't wait to beat it in a few hours most likely. I'm at one of the final stages right now.
UPDATE: Just finished Syphon Filter 2. What a wonderful game! I think I will not proclaim it as my favorite storyline in the series - even over Dark Mirror. Even with the downgraded graphics, if you can learn the controls then the game is really a blast. Now on to Syphon Filter 3!
I decided to return to this game after nearly a three year break from it. I've already beaten it before but I decided to return to it since I wanted a difficult action game to play. I started a new game - for better or for worse. The reason I say this is because this game is so incredibly unforgiving on your first time through while playing on normal mode. If I was to sum up the difficulty of this game in five words or less then it would be as follows: This game fucking hates you!
I've played Ninja Gaiden and Devil May Cry on the hardest modes and those are pretty much equal to the difficulty that is faced on normal mode in Chaos Legion. Normal enemies in normal mode sometimes have an incredible amount of life that will force me to wail on them to no end. It's like some enemies are devil triggered. And to think that Chaos Legion has a hard mode... That's one of the main aspects that I enjoy about this game though. It's hard as hell. Well, that and the legions, because the legions are fun to use and really help out for some of these harder enemies.
I was thinking about trying to get all the Thanatos chips this time on my way through. Maybe that would help out for the final areas just a bit.