Note: This game is included in the Hello Fangaming Time Capsule.
Trivia
This is Hello Fangaming's first game that can be played as a multiplayer game. A single player can also control both characters at the same time.
This game features lots of difficult co-op puzzles.
The game's controls are set up so that you can play as Mario with your right hand, and Luigi with your left hand. At the same time.
The game has a bug where the lives never go down.
This game was created using an open source SMB2 engine Hello Fangaming released in the past.
The abbreviation of this game is SMB:DD. This abbreviation was also used with Super Mario Bros: Dark Days. Surprisingly, out of all of Hello Fangaming's games, this is the only case of this happening.