Cool implementation of the Flatland concept - I have also thought about making a simulation of Flatland before - turns out it is pretty difficult to comprehend haha. I had an issue where since the mouse isn't fixed to the centre of the screen I couldn't turn a very wide radius. But you don't really need to move a lot so it wasn't much of an issue.
I thought maybe the dialogue should start automatically as I found myself wandering around for a while before remembering I was supposed to press space!