March 20, 2017 at 9:35 am #967
In the editor you can switch levels at the 4th tab (the icon with blocks).
In the game, you need to add doors. This is on the 3rd tab (person icon), and then below it click on the door button. There you can add doors, and when going to the properties, you can select the target level.
Hope this helps.
As for combat, it is not implemented yet :(. And now the question that I ask everybody: do you have a preference of which type of combat? Action or turn-based? Or something else?