While not a "proper" successor to its heritage, a good game nonetheless.
I can honestly say "I was there" (well, a year or so after) with the original game on the PC. It played well, but had a wafer thin plot (your corporation wants to take over the world) and nothing in the way of characters. You knew nothing about the agents, bar the intro movie which involved kidnapping someone off the street and going to town with some brainwashing and cybernetics.
Syndicate these days has character, and you feel much more like the world makes sense and corporate skulduggery is going on around you in an uber-high-tech world. The gunplay and weaponry is nothing particularly new, but the "apps" and battle-hacking are excellent ideas that superior titles like Deus Ex could learn from.
You can turn enemy superiority on its head by persuading one to fight for your, even disable enemy grenades, shields and missiles mid-flight which makes the skills genuinely useful rather than a token mini-game and adds a separate dimension to combat - although on the opposite side, if you're quick enough you can easily bunker down and intercept grenades against less proactive enemies.
This game has aspirations of being a DX:HR RPG, many of the settings are visibly large (if not always accessible) and once again show you the 2069 world much better than Jensen's 2027.
But you know early on that this is a shooter and that's what the designers want this particular game to be. You can acquire various upgrades along the way to help you (health, extra ammo capacity etc.) - but first and foremost this is about shooting your way to victory, even if for short periods you're unknown to your enemy (dashing your hopes of a stealth-em up section).
I would expect it to go To The Top of your games list, but it's worth a play this year.