If in tutorial mode the end of the quest is not accepted with the OK button but the window is closed (X), than new quest commence, but the next level is not given. Thus the next challenge can not be done (not the required level given). Game stops and player is unable to correct it.

See Hagar24. Tutorial level three finished but not used OK and stuck in level 3. Next challenge is building a stone mason which is only possible in level 4.