lets say that the mongol fleet didn't drown and wasn't destroyed by a storm and actually landed on the shores of Japan ... do you think they would've conquered Japan?

Of course

it's hard to say, The inhospitable territory in japan and incredibly proud citizens would make it an incredibly hard fight. The fact that Japan is an archipelago doesn't do the Mongols any favors ether. In my opinion Japan would be able to repel the invading forces but sustain incredible damage.

Mongols themselves are from an incredibly harsh environment ... I doubt it would effect them much .. they won on all terrains, from the deserts of the ME to the frozen deserts of Russia ... they even won some campaigns in Vietnam IIRC, this is dense jungle Vietnam ...

yes, but japan is over seas with mountainous terrain. the Mongols dominated because of mobility, and quite frankly I don't think they could achieve the same success in an archipelago.

preid you ever beat the Mongols in Medieval 2? As in eliminate them lol

I don't own ME 2, I am however,to a limited extent, knowledgeable about both Mongolian and Japanese styles of war and troop composition.