First phase is perfectly fine. A few volcanos to avoid, and some well telegraphed attacks that keep the player on their toes to look for the signs and dodge the damage.

The second phase being an absolute meat grinder of random bullshit is atrocious design. Random spike later falling from the sky. Tornadoes spawning under your feet constantly. Quadruple the amount of volcanoes that are in phase one. All while the boss has a hyper aggressive version of his phase 1 attack pool.

Nobody’s build should be expected to handle this in Act 2. Sanctum bosses were designed for endgame builds who have already ascended in POE 1. I actually think the rest of the sanctum was finely tuned up to the final boss. (Aside from getting a chalice challenge with an elite who passively regains health.)

And before anyone says “get gud” I have beaten the boss. But it has made me want to quit this game unlike anything else. Ascending is supposed to be this absolute hype moment. Finally unlocking your class’ true potential power. Well I don’t have that power and I’m being put against Mount Vesuvius and I’m just a helpless Pompei.

Lastly when you die against RattleCage the game will not let you respawn without exiting to the character screen. Which on controller on PC doesn’t work. You have to hit escape on your keyboard but the first time this happened I thought my computer froze but nope it happens every time.