Only the first time the game is run, a menu is shown by the Ogre rendering engine, to choose some graphics options, as the window size.
If you want that this menu is shown again in a next run,
you have to delete the Ogre configuration file:
~/snap/lostmem/common/.cache/G3D-2015/ogre.cfg
( "~" means your home directory).
When you enter a new scene don't run. Moving isn't stopped during the scene change; you will find yourself in the middle of the new scene.
To run on all systems a basic OpenGL is used, the movements can be a bit slow.