Hi there and thanks for taking the time to comment.
The download version does not need to be updated since it is only a web view the game (it is always up to date).
There is a link to the hosted version on the website which takes you to https://play.isleward.com/
Playing at that link is much better than the 'embedded experience' that itch.io offers and also fixes your right click problem.
EDIT: I've also updated the game page to provide that link now!