I started a legendary run of the legends campaign and proceeded to use the downtime between the opening objectives to search for valuable tools like first golems or towers. When I did get back to the objective, I managed to destroy the night portal just before the game takes off, and once the cutscene played i found myself unable to build and unable to leave the well of fate spawn. I also think that the game area might have been unloaded, as the terrain i could see was jagged and not very far off. Attempting to exit the game caused me to be stuck eternally on the loading screen.