Caliph

Same here. I get to log in my primary PC (w8) but i get the "Authentication Faliure" error when loading the game at my brother's (w10) with a clean account in a recently formatted PC. The error message is displayed before any actual login attempt is even tried, so it's clearly a bug. I would be glad to receive any updated info on the topic.

Including tips on how to improve performance would be nice as well.

THIS. It's specially annoying when you purchase a craft to stretch the boss time: It's useful, but It feels like a penalty until you can level up your girls enough again. Adding a skip-boss button or a toggle to enable/disable would help a A LOT.