Nintendo Switch Online has added more games to the Nintendo Switch Online Gameboy app. Originally released in 1989, and oddly missing from the original lineup, launch title Super Mario Land has finally been included. This is Mario's adventure in Sarasaland, and also marks the first appearance of Princess Daisy, before she became a pallet swap with Peach.
With it comes another 1989 title Baseball, which is just baseball, and Alleyway, which looks a LOT like Arkanoid. You get access to these titles with the regular Nintendo Switch Online subscription, and I can only believe they will just carry over to Nintendo's Switch successor. With all these games available at launch with backwards compatibility, it'll be a day one purchase for me for sure. These are all available now. So fire it up.