Tiles are 32x32 in size, but should be drawn in 128x128 and then scaled down, enemies and other game objects should roughly follow this size, tiles needed will be this (probally a few more to add more randomness and to make translations smoother):

There will be two tile themes, one will be 'ice', ie. normal ice, snow tiles, while 'darkice' should provide the look&feel of a cave under the ice.

There hasn't been a final decision on the graphic style, however something like this might be used (ignore the background and the Windstille hero):