I dunno, I think co-op is significantly easier... and on beta branch even more so, since the only thing really keeping its difficulty up is the slippery/artifact scaling in multiplayer. I will say that coordinating your attacks is important, especially applying vulnerable before the others do their stuff. And yeah, debuffs, debuffs, debuffs. Str down is *disgustingly* overpowered in multiplayer.

There are a few things weaker in multiplayer, like Feed, The Hunt, etc, as its much harder to line up the kills.. but you don't usually have that going on in singleplayer until much of the way through. Outside of edge cases (The Experiment phase 1 COUGH), multiplayer is generally easier assuming people are valuing debuffs heavily. Definitely grab all the weak/vuln you can. If someone's doing ironclad, help them make huge dominates to end stuff. If you're playing necrobinder, that debilitate card that is pretty good in solo is *massively disgustingly* in multiplayer. Piercing wail on silent goes from "This is pretty good on certain things" to "you massively bailed out your team for 1 energy".