I have a few suggestions about Europe. Scotland should have a few mountains, and should have very little tundra. The coast of Norway is actually very temperate, like the Pacific Northwest in the States. Adjust accordingly. I also think a lot of mixed forest in places like Europe, North America, and parts of Asia would be nice, with more pines at higher latitudes and altitudes and the like. Spain looks a little weird, maybe a few tiles added to the top edge would be helpful. Other than that, places in Central Asia look pretty barren, and I realize that it's pretty hard to amend that, but maybe some scattered forest, hills, a few rivers (with forests on the banks) and things like that. Great map though, and very big.