Hi Craig,
If you refresh the page, the Spacebar will probably work again (this happens occasionally…).
Also, you have downloaded a 2.8 version of the excercise:

This works in Blender versions 2.80 up till 3.4, but not in 2.79 or before.
I think there used to be a pre-2.80 version to download as well, but that might not have made it through the migration to Mavenseed.