Interested. Pandajs is not my main engine, but it looks easy enough.
Do you need the leaves to also interact with something besides the floor? Because physics is not really compatible with the particle system in panda, so you'd need to do the movement manually - the simplistic particle system doesn't help here a lot anyway.
I assume you want something like this only in 2D: [login to view URL]
Do you have artwork for the fire and leaf particles?
best regards,
RentAGuru