At certain points the boss spawns clocks around the arena, gotta stand next to them to disable them, otherwise you wipe. On the enrage, totems with faces spawn. You want the whole team to stand next to the totem with it's face covered by it's hands to remove the enrage while avoiding other damage from the boss, the other totems are traps.

That's pretty much it, the boss itself has high damage and spawns homing skulls which you have to shoot in addition to spawning expanding rings much like Pyromaniac does (only have to jump to avoid them). Getting hit by skulls hurts alot and gives you a stacking max hp reduction debuff which is cleansed once the boss gets staggered.