The optimization update renders the game unplayable, as the game closes as soon as everything loads.

His bullets are there and he can jump and get hit but his character dissapears for me for some reason. When i start the run he is there and then dissapears.

After I beaten the game on Merciless difficulty on my first playthrough, the achievement did not pop up. I was hopping I can stack the Normal difficulty clear achievement when playing on highest difficulty yet it did not pop either.