I know that some of players are ranting about the difficulty and how numerous and unfair enemies can be.

I wanted to tell my experience more precisely because reviews are too short to explain everything.

Mother Russia Bleeds has been tailored for local co-op.
Okay I have to admit that you can see clearly but it's not as unfair as people says.

Enemies come in packs of 2 to 6. Some of them requires special techniques.
As an example: never engage a dog without a weapon. If you rant because the damm beast chomp your face all the time... it's because you didn't noticed the electric pôle near you...

Also, like Hotline Miami, you can throw weapons and even enemies. You must learn how to manage crowds and time your drugs uses accordingly.

You see a green dude coming ? Keep him alive as long as possible. Take a "super power" fix and slaughter all his buddies and them grab the last one. Send him out of the screen and "pump" the green one during that time.
Note that drugs can be used to refill your health and you can even "pump" drugs on animals.

Punching an enemy can reach others around him, make sure to charge your punch and regroup enemies to hit a whole group instead of only one.
Learn that many enemies can grab you too. Hit the kick button to have a chance to get out of their graps.
Try to maximize the effects of your weapons by aiming the most dangerous enemies first.

Knives can insta-kill. Fire arms too. Aim for the head as usual.
Note that some clubs have knock-back effect that can really give you an edge during some fights.
Syringes dropped by junkies can also serve as projectiles and be used to stab... usefull on your first really badass boss...
Also the heavier a weapon is, the more knock back it has.

Edit: You can execute fatalities in berserker mode.
If you grab an enemy in berzerker, Ivan can crush his skull with his bare hands...

Projectiles can be intercepted if you use the grab button at the right moment.
Works well with grenades, knives and bottles...

TO CONCLUDE:

You can unlock new drugs with new cool effects to speed up your mass murdering skills.
Be merciless and take time to learn enemies behaviors. Nearly all level adds a new type of enemy and a new weapon.
Don't forget that characters have a range. Consider that before selecting one is important.

On this good luck, be merciless and have fun !

N.B: You can find few combos if you kick, punch during a jump.
Edit: each level gives access to an arena in survival mode. Beat scores in arena to get new drugs and add better options in regular levels. As an exemple, one of the drugs makes instant fatalities.

For sure a good point ^_^

Thanks for those useful tips :)

Very useful tricks indeed. I had figured most of them out already, and I've just beat the game so it's clearly not as hard as some pretend (though, this last f***ing boss gave me a damn hard time).

I just hope Le Cartel fixes the bugs quickly, this game has a real potential and, even as is, I truly enjoyed it.

Gracias for the tips!
I've been playing MRB and noticed the fluctuating difficulty. I even note it in my GOG review of the game.