Meh, I don't like the sync think. It was cool as long as it worked out, but I never restarted a mission just to get full sync, unless it was really important.
Some missions were fun to redo, but a good number of them had the hard part only happen at the very end. For example, I had real trouble with the mission where you use Leonardo's tank and must not receive a single hit for full sync. However, even if you die after getting hit and redo that part, it's too late. You have to redo the whole thing ago, and you only get the tank in the last stage of that mission. I tried two or three times, then got tired of it. Same for most others. The ones that say "kill X with Y weapon" are easy, but the ones with stuff like "don't get seen" or "don't get hit" are a royal pain in the ass.
