Just beaten this, thoughts below:
+Massive improvement on MWIII, better storyline, more cinematic missions
+Purchasable upgrades, although a bit simplistic in nature are always nice to have
+Managed to carry on the weird psyops vibes from prior BLOPS games without going overboard, there were a couple of 'creepy' sections but thankfully used sparingly at appropriate points
+Solid performance and good graphics
+I quite like the dynamic lean mechanic when aiming down sites near cover
+Good squad based combat.
-Some really silly persuasion sections which are so much on rails that there is no challenge. Press F on the prompt shown zzzz.
-Enemies are a bit dull and predictable
-Some missions are a bit short, or when long a bit repetitive (Hunting Season).
Overall it might be my favourite BLOPS game, although it's a while since I played one.