The Magical Dollhouse Game Over is an ending which occurs if the player obtains the Silver Key and do not enter Alice's room several days after that.
Coming back home from another day of training, Eric(a) and their team is surprised by Alice, but not by person, but in their mind instead. With the magic she learned from the Bee Hive all but the staff members have been converted into Alice's dolls, and Eric(a)'s group follows immediately.
And Marianne would've stopped Alice's charade here and there, if it wasn't for Isabelle who also became Alice's doll - despite being the strongest Magical Girl there is, she was already halfway to becoming a doll when Alice got into her. Unable to hurt her own daughter again, Marianne retreats with Olivia and Nele, leaving the dollmaker Magical Girl to create her own Magical Dollhouse.
Inevitably Marianne will come to take back her camp, but that is of no importance to Eric(a) anymore - they are now but one of Alice's many friends.