why doesn't the game work?

_update60() isn't working in the web player so you need to call it twice in _update() as a workaround.

Example :

function _update() _update60() _update_buttons() _update60() end 

This will be automatic in 0.1.9
For more information, you can refer to this thread : https://www.lexaloffle.com/bbs/?tid=3722