itch.io has an installer. When I click install, it doesn't bring up a file to install.
There is a 'Download' section on the game page, click on it, go through everything and it should start to download a zip file.
When you are done downloading, extract the zipfile by using 7zip or winrar ( you can extract it by right clicking on it and click on extract )
It should be all, tell me if you need more instruction :)