for level 15 throw the axe at the yellow wall on your right while jumping into the tunnel on your left. when the axe comes back it will kill the bat. recover then throw the axe onto the skull to remove the ghosts and get to the chest
Putting the game in a different window instead of another tab works for me on firefox. Also, manual save and loading always treats you like you've been idle for the whole time, so in case anything happens you should try that.
@Starlightann the assistant doesn't stop you from getting duke. Maybe it was because you needed more questlines complete or you didn't have all 3 endings
Numbers Going Up