Howdy. I know I'm late to the party here, but I also played Snowyhill and The Wintery Base. I liked Snowyhill because it made me nostalgic for a number of other worlds I played as a kid. I can always appreciate short worlds!
I also enjoyed The Wintery Base, as it had a lot of cool little ideas in some of the levels and a lot of the tilesets were unique. The puzzle in "Skelesnow's secret shack" was an absolute pain, but it was manageable. I usually play on hard, and as a result, killing those "Maggot" Cryozoids on "In the enemy's attic" was actually impossible without cheats, unless I was missing something. Other various levels were just incredibly hard, like "The Infected Sewer" and "Stan's army," and I didn't have the patience to try to complete them normally after giving them a fair chance. I also only got 90% on this world after completing all of the levels on the overworld as well as a few secret levels, so there must be a number of well-hidden ones that I missed! I may go back and play them in the editor at some point.
Anyway, thanks for the worlds. I'll probably end up posting a few of mine that I never uploaded here and there at some point, given that I remember.