Saved games for Syndicate has constant size and are not coded or compressed in any way. They consists of three main parts:
You can find more information here:
Harrisonf Games Site[internal copy]Some savegame editos are available in Cheats section.
Note that American Revolt savegame is a little bit different from Syndicate one.
Partially reworked Syndicate savegame files:save\0?.gam