I too am playing full version and there are no other buttons or anything that allows me to interact with Malo more than just petting her, even after acquiring all hearts. I'm not sure what the issue could be.
Hello, are you by any chance playing on a resolution that is not 1920 x 1080? that may be the issue and im currently working on a fix :)
Edit: A new version of V1.2 has been released that fixes this resolution bug. You can try it out and see if its fixed for you. If not, try and run the game in 1920x1080 as it is built for that resolution.