Yu-Gi-Oh! 5D's Tag Force 6

[Girlyvader]

Game almost fully works on my HTC One M8 with the latest PPSSPP version; I can walk around in the story mode, the cutscenes I can access work without any lag issues, in short the game seems to be fully functional... until I actually start a duel. When I duel, the game breaks; framerate drops to 8-10 FPS, audio turns into a laggy mess, the duel background doesn't load, etc. I have confirmed that it doesn't appear to be the iso itself (the same iso works fully on my computer with latest PPSSPP), and fiddling with the settings doesn't seem to affect it [also, tag force 5 works just fine on my phone, so its not just a lack of memory]; any ideas on how I might try to remedy this?