The latest version of Itch.io is installed.
My OS is Windows10 familly 64x. And I tryed with a fresh windows installation too (same problem). All drivers are up to date.
ALL webGL games doesn't work for me.
My specs : i7 920 / 12go Ram / GTX 1060 / Gigabyte GA-X58A-UD7
This is how your exemple is show in my application :