Cemu

the game suffers from texture corruption after extended playtime periods, some textures, specially alpha textures will start to flicker and change colors after playing for a while, it can be fixed by restarting the emulator, this issue happens in OpenGL mode
in vulkan mode the game runs at single digit framerate, menu and intro runs fine
game is close to run flawlessly and could use some optimization, it runs on a modified version of UE3 made specially for the Wii U by the original dev team so i doubt general optimization updates will fix it over time
the issue can be seen in the black flags in the screenshot attached and there are some more examples here https://imgur.com/a/1wgn62C