It's easily the most unenjoyable game in multiplayer. Half the time your teammates are clueless as to what to do or where to go. You make zero money playing it. The game is often over in about 5 minutes. Awful.
All of the "domination" type modes suck. Seriously, couldn't ND have thought of some other objective modes? King of the Hill, Turf War, and Chain Reaction are practically the same except for a few variations.
I happen to think Chain Reaction is the second most fun game in Uncharted 2 online - first being Plunder.
First of all, if anyone can't figure out what to do in Chain Reaction, they must be ****ing idiots, or under 12 years old. Seriously. I can't imagine how a functioning person wouldn't figure it out in one minute.
Secondly, don't use idiots as a reason to criticize an otherwise good game. If everyone plays it correctly, which everyone should, then it turns out to be a very strategic and long game.
I like chain reaction, one thing I like doing is grabbing a power weapon and go where I'm near area 2 and 4, and depending on who takes 3 will go to the area that needs to be taken. :) Once the enemies come they don't even know what hits them, this is especially easy in the temple.