Not too many new things and that's probably for the best.
Blood Money is no exception to the rule - get a target, choose your method/style, walk around, map out the plan, navigate, think, put the pieces together, best way to go, kill some poor guy who's taking a leak, take his outfit, blend into the environment, hide the body, kill your target and escape. After 50 mission like that (and lets be reasonable - many of them are similar) it gets a bit daft and boring. I am certainly a fan of the series but after 10 years I think I've had enough, unless the next instalment will bring in something revolutionary while remaining true to its own unique style we all so much love.
On blood money - the AI is still a bit moronic, the levels are very nice and fun and different (but again - some of them we have seen before), the guns are customizable (you can buy add-ons for your special weapons), the save system is OK, depending on level of difficulty, ragdoll physics and graphics (the engine) is ok but not top-notch, variety of weapons and enemies is good, ways in which to complete a task is VERY good (as in - a lot) so replayabilty is high. Sometimes you get stuck, a few bugs here and there (which, if the game crashes, make you replay the whole level because save games are deleted after each level) but nothing major (except that one level which crashes if you drop something from your inventory). A new interesting thing is the level of "notoriety", which means if you go out guns blazing then the next level you will be recognizable. The concept is good.
As far as the story goes - we know the characters, the agency and mostly nothing has changed. The storyline is so-so, cinematics aren't great but the ending is very nice and rewarding.
All-in-all a fun instalment and the score would be higher if not for the amount of hours I've already spent on these series. Feels like we're running around in circles. Still - beats the movie any day ;)