12000 BC (Chrono Trigger) - This era probably has the most interesting stuff of any of the game's time periods.
Donkey Kong Country: Tropical Freeze - Basically the entire last batch of levels in the game.
Mount Gagazet (Final Fantasy X) - I really like the cold and forboding atmosphere of this level, topped off with one of the hardest bosses in the story.
Mount Wario (Mario Kart 8) - Stands out for being one of the few Mario Kart tracks to be a single track divided into thirds instead of being a course traversed three times. Creates the fun sense of speeding down a mountain like one is sledding/skiing. Level design is solid and the aesthetics keep on changing while remaining on theme.
Snowdin (Undertale) - Does a good job at introducing this underground society to the player, emphasizing the oddly cozy portion of winter holidays. The puzzles present are cute additions, the local characters are fan favorites, and there are plenty of fun and funny moments.
Snowpeak Ruins (Legend of Zelda: Twilight Princess) - The dungeon is designed to be a reasonably convincing abandoned mansion, which is a cool setting for a Zelda dungeon. There's a fun gimmick of searching the mansion for ingredients for a stew, which is used for healing instead of the usual Hearts in broken pottery. Then you have one of the best mini-bosses in the franchise and a fun new item to use.
Love and tolerate.
