pretty original map, well done!
the gameplay is pretty good, but u should put entinity "base" more into the ground, at some points, they r floating.
the lighting could be better (use a lower ambient, because it seems like its just as bright inside the houses as outside =s) and the geometry could be better (like as example, u could make the snow on the roofs more round and random, so it looks more natural.
the pickups arent very well. theres only 1 greenarmour and no yellowarmours, while there r 10 healthboosts and 2 quaddamage (suggestion to replace 1 quaddamge and 1 healthboost, for 2 yellowarmours).
further, why there's at 1 base some kinda odd ladder, while theres a much better 1 (even tough u should noclip the vertical bars, because they hold u down at the upside) at the frozen lake?
could u plz make more vertical freezed bars (srry dont know the english term 4 them :P) in place of 1 type? that should make the map more natural 2.
at most houses, u c a chimney, but no furnace or something beneath it, maybe a suggestion to add a furnace (or something in that direction) or remove the chimneys without furnace (or something in that direction)?
anyways nice map, just improve it a bit :P.
ill give 50 points for now...
