>>9597302Tamagotchi Nanos are smaller and much more simplified versions of the 90's Tamagotchi. At first they were just remakes of the original, but with more simplified controls, and your baby evolves straight to adult instead of spending time as a toddler or teenager. They're very low maintenence. Honestly the first wave of these things were pretty lame. But later on they did collaborations with a bunch of anime, Pokemon, Pac-Man, Star Wars, Hello Kitty, and a few others. I only know about the Hello Kitty one and I still think it's kind of lame.
If you intend to buy a 90's one to play with, I suggest going with a gen 2. The characters are better in my opinion, and they actually improve the minigame so it's not just pure blind guessing to win. You can recognize them because gen 1 has checkered background while gen 2 has wavy.