"Current version has at least five hour of gameplay." I am wondering since its RPGM are those hours actual content or is it hours of grinding and trying to find your way around a mess of a map?
not really, compared with other grinding ones, in which you need to repeat the same thing again and again (I think this is the definition of "grinding"). The map of this game has been nicely organized by subway and dirigible balloon, and you would be given a sign to indicate where you need to go. In other words, you would be mostly restrained in a small map with signs at one time. If you follow the story, it would be fine. However, it is still RPGM, don't expect it comes as easily as Ren'py, you still need to spend some time on the way of your adventure, you also need to explore the same map if you don't know how to trigger the next event --- nothing to do with the map, sometimes you need to speak with the right "NPCs", for instance.
