Allow me to elaborate :
sorry i didnt see the emu you linked there but i get different results, the flashing in the sideborders remains so i'll assume thats on purpose tho not sure if its supposed to be only a few scanlines or if the intent was to flash the whole border, that persists on both emulators , it wont run on a mister so i cant test and i definitely dont have a real machine.
On the java emulator my ship looks like the one in the screenshots to the side here, on the emulator you linked it looks different.
On the java emulator i dont have sound, on the one you linked my bullets look different (lol) ... goldorak is pure nostalgia to me from when i was a real little kid (even smaller than the guy in the picture) so i cant help but like it but im hoping this isnt "the final version" yet ...
also if i put the java emu on gx4000 the joystick wont work and i cant get past the title screen ...
fyi
(o : i definitely like your style, shame theres no mister core to feel the real thing :: -- thanks for the assets btw who know we get a jaguar port by 2030)