This game resembles the Sierra-style labyrinth sections, isolated into its own little game.
I think the map drawing mechanic could be expanded on in order to increase the potential of the game. Right now, if you run into a problem drawing on the map, you have to erase it, by hand, and start over. External tools can do that job better.
To solve this, you may want to consider giving the player extra pages to draw on, so that you can reference your original drawing when having to shift your drawing or backtrack on it. You could throw out pages when you have a new, better page to reference from. That way, you can keep your drawing process clean.
You don't see this type of game literally anywhere. Keep going on this project, you might have your own niche!