My deck. Fusion is THTD.
I use Fusion gate to avoid using a spell space. Storm is to remove his nightmare wheels at the end. DO NOT summon piranha until they're destroyed on your final turn. I prefer storm because I got screwed by ceasefire being my final draw in one attempt.
That wacky magic keeps the shadow game damage to a minimum, and I recommend using benevolence on your healing cards unless you're trying to get low LP bonus. Rain of mercy helps keep Marik from burning himself. Only other thing to worry about is getting yellow luster shield in time.
Also, don't summon THTD until the final turn. Make sure you do so before you activate storm, if you choose it over forced ceasefire.
Final turn:
•Activate fusion gate
•summon THTD
•Use storm (Yellow shield and fusion gate should be enough, but set another card if you want). He will activate both nightmare wheels, but they won't matter as you're not attacking with THTD or labyrinth