A challenging game, especially in the hard mode where the time limit can be unreasonable. I have to reset the scene several times just to finally get all three stars. I thought the medals were broken at first but then I decided to test out the easy mode to see if there is a requirement to get the medal and turns out, that's what it is.
To those complaining about the broken medals, they're not broken, the problem is that you have to get three stars every time up. Once you complete that, then the medal will finally unlock. The only issue is that the author wasn't specific on this kind of thing.