Yeah, ill probably get some hate for this, but imo the final boss on cm has like... no mechanics except for these 2 or 3 spirits that appear. Compared to the normal mode it's much much easier.
For example, the fire phase in normal mode drops huge meteors onto 2 players, so that alone forces you to coordinate. Plus you have to get behind a rock. Cm doesnt have that.
Or the last phase where the boss would cast big water orbs everywhere - purple laser hitbox in cm is nothing in comparison.
Or the super confusing blue glue thingy you have to get in while the floor is littered with water lines. Cm doesnt have that combo either (yes the spirit of grief but no water lines or anything similar).
All that cm does is increase the aoe on players, so you have to run away further apart from each other. A laser show, thats basically it. Its also 1000 times easier to understand whats going on in cm, because in normal once again the final boss is just a bunch of effects cluttered all over your screen.
(Beside that i love the level architecture)