Although he is always upstaged by his fat brother, Mario, Luigi is
obviously more skilled. He can run faster, jump higher, and doesn't eat as many pizzas. He also sucks nasty ghosts up with his trusty Poltergust 3,000. He can do all of this... and all Mario can do is shoot water at stuff with FLUDD. Luigi isn't just the most underrated Mario character, but the most underrated
Nintendo character too.
In 2D platformers, Player 2 is always Luigi. Luigi has only had two games starring him: Mario Is Missing, which shunned Luigi more, it being a crappy edutainment game, and
Luigi's Mansion, which was a lot better and introduced the trusty Poltergust 3,000. Both of these involved Luigi saving Mario, which shows how lucky that fat-ass is.