I don't remember if I tried using the spacebar, sorry. I know that I clicked the buttons and that did nothing. I refreshed the browser tab and everything loaded correctly.
That is interesting. Probably the CSS file did no load correctly and hence the buttons displayed nothing. At least for next time I now know that I should add some sort of a delay for the CSS and text data to load into the game before throwing the player straight away into the game. Thank you again.