Thanks, we're glad you enjoyed it! Yeah, that attack is the hardest one on that boss. But it is also when you can deal a lot of damage! When he is static summoning the rocks, you can shoot+melee him from his side before running away. And you can jump over the fire wall to the edge of the room as the wall disappears, but you almost always end up getting hit by at least one rock, sorry ^^". He is hard, we wanted him to have that "final boss" feeling but we may have overdone it.