Finished Deathloop the other day. Brilliant concept, although actually much easier than you'd expect. You have to die three times before the day resets, which means it very rarely happens, and you can infuse weapons and gears to keep them even when you loop, so after a few hours of gameplay you're well equipped at all times.
The four areas are pretty small, albeit densely packed, which means you can blast a path to your objective once you get to know that part of the world. And the slabs are good fun, particularly the Nexus one which allows you to link enemies so that a headshot to one will kill everyone in the chain.
It's the look and feel that's most rewarding, and the game is just good fun - particularly the dialogue between Colt and Julianna. The game really comes to life when she invades (either controlled by the computer or an online player), as she'll suddenly come gunning for you. But if you have the invisibility slab, it's fairly easy to beat her - just wait for her to get near and a few shots to the head should end her.
All in all, I think what felt fresh for the first two thirds eventually became tiresome. You're constantly having to complete the same levels - there are four distinct areas in the game, although each can be played at morning, noon, afternoon or evening and they change completely each time (new enemy patterns, different bosses etc). But once you're deep in the game, you're a bit bored of going back to the same area for another bit of information. Although by that point you can at least destroy everything in your path fairly quickly.
So yeah, great game but perhaps made to be a little too easy.