I've been testing GC games with lakka recently and have gotten some playable results while messing with the dophin's in-app overclock cpu settings. So far I've tested Melee (playable at 20-40% cpu overclock), shadow the hedgehog (playable at 30-40% cpu overclock), viewtiful joe (1& RHR) (playable w/o cpu overclock), Twilight Princess (sorta playable w/o overclock; lags in big areas), kirby air ride (sorta playable at 20-40% cpu overclock), luigi's mansion (playable w/o cpu overclock), and super mario strikers (playable at 20-40% cpu overclock).