Rent it.
Good:
The new art style is surprisingly great.
The talent tree.
Gameplay.
Story.
Bad:
Very short storyline.
Very short co-op campaign.
Voice acting is not great.
Voice cast from original gone.
Summary:
The addition of a talent tree was intresting and fun but lacking the ability to switch power like in the original was a clear step back, you cannot impale with your demon arm, cant shoot black holes and demon guns are gone as is using your demon arm to scout about etc.
You get black holes as random drops off dead ppl, have a short gun channelling thing and a swarm ability which stuns enemies for a period. Gun channelling and swarm are on timers. You can how ever pick up objects and impale or slice ppl apart which is great fun and you can execute or slice people apart with your demon arms. The lack of the original voice actors for jackie and jenny are all-most criminal as they did fantastic jobs in the original.
The talent tree has nothing exceptional or inspiring and is fairly basic but still adds some fun to the new game+ mode if you want to play again but this all seems just like its there for you get the 50g for playing new game+.
Running though the game and co-op on hitman level didn't even take me 10 hours including the hitlist and vendetta co-op levels which is frankly shocking for a full price retail game. As much fun as the game is its entirely to short to warrant a buy imo rent first.