If you own a Nintendo Switch and pay your monthly subscription to NSO, you must know that Nintendo gave you Super Mario Bros. 35 as a present for the mascot's anniversary. The simple platformer/battle royale hides a nice easter egg: Luigi is a playable character. To play with him, you only have to meet a requirement and press a button, that's all.
'How can I unlock Luigi in Super Mario Bros. 35?' First of all, you need to reach level 1 star, the equivalent to level 100, by playing and getting good results. Once you are there, you just need to hold the L button while entering a new match and suddenly the character on screen would be Luigi. He is exactly the same as Mario, but with coloured clothes.
Take a look at Luigi in this video by CombotronRobot.