No need to apologize! BE is Breast Expansion, a feature that's not actually available in the public demo, but has been in Patreon builds for some time now. There are enemies in the game that will make Alicia's breasts larger with certain attacks, and when in that state, the H-scenes change as well. Previously BE used to slow you down immensely and prevent you from jumping, so it's been in need of an overhaul for a while now.