ok so this worked perfectly for my mum when she tried to play the game, exept for the last bit (the bit over the drawbridge). she mastered th simple ledge jumps up the big stairs but struggled with the jumps accross the void because according to her it wasn't "obvious when her feet were at the edge of the platform", so she kept over or underestimating when she was at the edge, leading her to either fall in or jump in. another problem once she finally managed was that she jumped accidentally onto the railings of the treadmill bridge skipping entirely the act of pressing (w), (space) and (shift) at the same time, and so she got stuck as she didnt start to fall back, which is supposed to allow you to open the door.
Other than that the game worked perectly to teach her how to move and look around in a 3d environment, and how to interact with objects.