2-1

2-1 can refer to the following:
 * World 2-1 from various games
 * Level 2-1 from various games
 * Stage 2-1 from Donkey Kong for the Game Boy
 * Hoo's Wood 2-1 from Super Princess Peach
 * Chapter 2-1 from Super Paper Mario
 * Area 2-1 from Mario vs. Donkey Kong: Mini-Land Mayhem!

2-1