Super Mario Bros. Melee
From Mario Fan Games Galaxy Wiki
The very first "serious" project gamester worked on in the early years of his fangame expertise (back in 2003). The game attempts to emulate classic Super Mario Bros. 3 battle modes for two players and also included a "death match" mode for players to attain various SMB3 powerups to duke it out across several different levels.
The game was later scrapped as gamester moved on to bigger and better games.