Deal With the Devil
I'm pretty sure all the medals are broken in this game since some time in 2019 when the last unlocks occurred.
Problem is, the game was originally released as a Flash game, and the medals worked in that, but it was also released in such a way that, if you did not have Flash, then an HTML5 version of the game would instead load but unfortunately the medals never worked in that.
One might think a potential workaround is enabling Flash plugin in the browser (see my signature for an example of such method) but no dice. The HTML5 version seems to be what loads, rather than the Flash version, even in browsers with Flash plugin enabled.
And I know for fact I've completed the requirements for at least one of the medals I'm lacking, and not been awarded it.
Ideal would be if the author would port the medals to HTML5 as well.
Having both a Flash and HTML5 version of a game, is a novel approach I've not seen on the site before, but unfortunately since the medals were not implemented in the HTML5 version, and since that appears to be all that'll load anymore, I have to conclude broken medals game unless someone has some more info on this or some workaround.
----edit----
And as an extra bonus, it appears the game doesn't even work anymore, at all. You can insert the coin but then you cannot make any selections after that, either in Chrome or Firefox.