I did some experimentation back in March, but it wasn't my work, I've found that Dwayne Slater (ds84182 on github) has made some modifications (with SDL) to get it through https://github.com/ds84182?utf8=&tab=repositories&q=flutter
I was able to get the gallery on, had to do some tweaks (like enforce binary mode when reading files, and certain other things, but haven't looked since then).
There's also this project which uses Go to run Flutter on Windows and Linux: https://github.com/Drakirus/go-flutter-desktop-embedder
Is your Windows implementation publicly available? I'd be curious to check it out.