The game is visually a little bare. Here are some ideas how you could make further changes to enhance it:
The tiles could have rounded corners, to look a little less sharp. The border-radius property of Rectangle can be used to achieve that.
In real world memory games, the back of the tiles often have some common graphic. You could add an image with the help of another Image element. Note that you may have to use Rectangle's clip property element around it to ensure that the image is clipped away when the curtain effect opens.
Let us know in the comments on Github Discussions how you polished your code, or feel free to ask questions about how to implement something.