There are screenshots in issue [0] shared by users. My MacType profile repo [1] also has screenshots for comparison. You might see differences between screenshots because MacType works with a profile containing customizable configurations which can tweak font rendering behaviors as per demands (and I think this is why the README does not include screenshots).

[0] https://github.com/snowie2000/mactype/issues/557

[1] https://github.com/chawyehsu/mactype-profile#screenshots