I know this is a GCW Zero development forum and this concerns a conversion done for the GCW Zero, but please, could you backport the improvements you did to the f2bgl engine and upload them to the engine's github? So the improvements could be applied to the Windows build too.https://github.com/cyxx/f2bgl
Some of the last improvements done several months were done by the original author (cyx) because I contacted him a couple of times and offered to do testing and reporting info for bugfixing (I did this with REminiscence too, also developed by him), but unfortunately and except for some small fixes he did based on my reports (for example, he added a feature for additional languages and fixed some major crashes), he generally lacks time and motivation to give this the big push it really needs to support the game properly. And I myself lack skills to do anything with it unforunately.
PS: If I understood right, there are two separate development branches of the engine being worked by you guys and one of them hasn't been released?