You can play with up to four players, and the game will adjust difficulty accordingly. I only really got to experience it with three, but found a noticeable difference. You can revive your teammates with syringe charges, but also set each other up. Using a baseball bat one player can wind up his swing before a second player pitches an enemy at him. Home run.
Unfortunately, as the game progresses, this simplicity starts to fade away, replaced with incredibly durable enemies and confusing mechanics. It's good that they mix things up, really it is - but not all of it works. One fight will see you avoiding snipers, the other avoiding grenades. Perhaps this time you'll need to jump over pipes as a train moves through a railway tunnel, or avoid those lethally fast trains yourself as they hurtle along the tracks.
Mother Russia Bleeds hits on an incredibly successful formula and the quality is evident within the first 15 minutes of punching bad guys to death, but then it squanders that quality by tossing different elements into the mix. In fairness some of these work, but the hit rate isn't great and several of them end up just being annoying. One thing that stands out is the addition of Russian soldiers with rifles. Getting shot from off screen and losing half of your health is a particularly odious design choice, and it grates every time you get killed because of it.
The same is true of the boss battles. Several of them work, but many of them introduce new gimmicks that are more often than not annoying. The worst offender has you trying to blind a commando wearing night-vision goggles using flashbang grenades to stun him in place so he gets hit by a train. He's flanked by two armed soldiers who can immediately knock you down so you'll drop the flashbang grenade and get stunned in the path of a train. If nothing else, it's just infuriating.
An arena takes care of many of these issues, so honestly, if you're really into beat-'em-ups, perhaps pick it up anyway. It's a fun game, and it isn't that I ever had a bad time, just that it frustrated me a lot. I enjoyed it and came very close to slapping one of the coveted "Recommended" labels on the review. Unfortunately, it's a game that starts fun and quickly becomes irritating to play due to a couple of design decisions. It's a great looking game, and by virtue of having some pixel art, a bit of blood and a decent soundtrack it'll probably be compared to Devolver's Hotline Miami, but this game has its own distinct flavour, and it's something you should check out, even if it's just a taste. Mother Russia Bleeds has a lot going for it, but in trying to keep things interesting, they've lost a little bit of what makes the game so good.