There is no requirement whatsoever for GPL-licensed source code to be provided with the binary. It just has to be available to recipients of the binary.
CC4 for the graphical assets
GPLv3 for the programming code
Also see https://itch.io/post/13347732
this only applies to distribution in a physical object (section 6c.1 of the gplv3) but what applies here is (at least how i see it) section 6d which reads as follows:
> Convey the object code by offering access from a designated place (gratis or for a charge), and offer equivalent access to the Corresponding Source in the same way through the same place at no further charge.
(this is only an excerpt)
the "equivalent access" is what i think is not given, since we have gratis access to the binary, but not to the source code.
but they promised to clear that up soooo...
cute game btw