Intravenous

Play this game on the 'True' difficulty.
The game makes one thing really clear; all your tacticool, RS6 Siege super edgy 'skills' mean nothing.
It is an unflinchingly vicious, no holds-barred stealth strategy shooter.
Violent only in the way that Hotline Miami is.
As stealth focused as the old Splinter Cell games.
If you think you can burst through doors with an AK and one tap your enemies you won't do well in this game...
Noise is a real REAL thing, suppressors don't make guns silent in real life, and they don't do that here either.
If you leave a door open, enemies will remember it being shut and investigate, if you leave a blood trail, enemies will follow it with guns ready.
Every single enemy is a tough fight unless you're careful, prepared or just straight lucky.
The loadout system is way more in-depth than I expected offering arsenals, armours and gadgets to match all play styles, but there's no 4 weapon carrying, heavy armour wearing, grenade packing stealth game-play. Guns and gear are loud and heavy and alter your interaction with the game world drastically. I prefer the stealth approach and not wanting to make any excess noise I run a knife and a suppressed pistol without armour, this means that my character is a ghost, but one single .45 wound and I'm dead.
Also the story is awesome, there's nothing quite like slaughtering a warehouse full of degenerates in the name of bloody vengeance.
The game will beat you down and make you a better gamer just get it.
It also has a lovely rage purging mechanic, hold down F to activate your mic and scream obscenities to lure your foes to you, or just to add to the rage of battle.
A solid 9/10 so far, will update going forward, well played Roman Glebenkov!

Someone really wanted to "fix" everything that was "unrealistic" in stealth games and this is the result. Guards are not stupid, suspicious activity is actually suspicious, silence is not silent and invisibility doesn't make you invisible. It's up to you whether that's a good or bad thing.

Who says stealth is even necessary? Just play on the hardest mode, blast them with a shotgun, and pray you survive

It's not a simple "huh who's there" and "must've been the wind" crap.
Game gets real aggressive once the enemy gets alerted, and it never leaves.
Also punishes players who try to camp.
Different to hotline maimi but you can feel it when going loud. (And changing the difficulty)
After finishing it. Would buy Intravenous 2.

Very fun stealth game that may seem challenging at first, but you feel like a trained assassin after learning the game mechanics. On the downside, it doesn't have a good soundtrack. It's a shame that if it had something similar to Hotline Miami, it would have been much better.

Soundtrack is really good, story isn't anything crazy and is pretty straight-forward but I don't really mind that. Good variety of weapons to mess around with along with many different ways to clear levels and progress forward. Very difficult and incredibly unfair, feels like you're getting your nuts stomped on 90% of the time. I'm into that though so thumbs up.

Hotline Miami like although more about stealth and with less surrealness. Worth every penny if on sale, can't wait to try the second game!