Where have you been?
In all honesty, just watch the quick look (if you already haven't) and then buy or pirate (which the developer doesn't seem to mind you doing) the game. I made my mind up and bought it on steam after about 7 minutes in the QL. A review for this kind of game is superflous. It is an experience, not epic poetry. Try to review drugs or sex to me.
I feel like I have waited a long time for this game. Most importantly for the simple fact that you are fragile, and each and everyone of your foes must be dealt with "respect". More so than in any other game I have ever played.
Each level (I believe) consists of one building with two or more floors. Each floor and their rooms can be seen in their entirety and must be cleared from enemies before you can take the stairs or elevators to the next and so forth.
There is great strategy to handling these floors without going in over your head. Melee weapons are silent, and most guns are loud and will attract foes all over the floor, which is synonymous with getting your ass handed to you 90% of the time. As there is no consequence to experimenting and probably dying (which is key to this game), there is as Klepek puts it a great joy to just going for it. That will probably kill you but it is also the best way to learn, and dying IS a part of this game.
This is mindless fun, and to me that is how gaming was born and still what it should do and does best. There is some trippy sidestory which serves as seasoning and doesn't get in the way of the experience, that is fine.
Pong is still the best game ever made.
Sidenote* I happen to play Mark of the Ninja(PC) parallel with this, it is a great game and all but is so EASY compared to H.M