Mario & Luigi: Superstar Saga is a surprisingly fun game. At its core it’s a role-playing game. But you wouldn’t tell because of the amount of platforming, the quantity and quality of small puzzles and -most of all- the funny self-deprecating dialogue.
As the player you control Mario and Luigi simultaneously and that takes some time to master. As you learn techniques along the way, each character get special abilities allowing you to solve new puzzles and advance on your journey. It’s not a shot game for a handheld, taking around 20-30 hours to finish at the minimum.
The 3DS 2017 remake of 2017 (Mario & Luigi: Superstar Saga + Bowser’s Minions) did keep most of the game as it is, just updating the graphics and music for the more powerful handheld. That’s says a lot about the original whose 2D SNES/GBA graphics don’t feel outdated today, but hip and cute pixel-art.
Have a look at “How to play retrogames?” if you don’t know how to play retrogames.